Methods of preparing a catalyst utilizing hydrated reagents

ABSTRACT

A pre-catalyst composition comprising a) a silica support comprising silica wherein an amount of silica ranges from about 70 wt. % to about 95 wt. % based upon a total weight of the silica support, b) a chromium-containing compound wherein an amount of chromium ranges from about 0.1 wt. % to about 5 wt. % based upon the amount of silica, c) a titanium-containing compound wherein an amount of titanium ranges from about 0.1 wt. % to about 20 wt. % based upon the amount of silica, d) a carboxylic acid wherein an equivalent molar ratio of titanium-containing compound to carboxylic acid ranges from about 1:1 to about 1:10, and e) a nitrogen-containing compound with a molecular formula containing at least one nitrogen atom wherein an equivalent molar ratio of titanium-containing compound to nitrogen-containing compound ranges from about 1:0.5 to about 1:10.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 15/953,930 filed Apr. 16, 2018, published as U.S.Patent application publication no. Us 2019/0314797 A1, and entitled“Methods of Preparing a Catalyst Utilizing Hydrated Reagents,” which ishereby incorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

The present disclosure relates to catalyst compositions. Morespecifically, the present disclosure relates to methods of preparingolefin polymerization catalyst compositions and polymers prepared fromsame.

BACKGROUND

An economically important class of olefin polymerization catalystsincludes chromium-silica-titanium (Cr/Si—Ti) catalysts prepared fromsilica-based catalyst supports. Rigorous drying of the water-sensitivecatalyst components used to produce Cr/Si—Ti catalysts increases thetime and cost of production. Development of an aqueous solution suitablefor depositing titanium onto a silica-based catalyst support wouldreduce the costs of production of olefin polymerization catalysts. Thus,there is an ongoing need to develop new methods of producing olefinpolymerization catalysts.

SUMMARY

Disclosed herein is a pre-catalyst composition comprising a) a silicasupport comprising silica wherein an amount of silica is in a range offrom about 70 wt. % to about 95 wt. % based upon a total weight of thesilica support, b) a chromium-containing compound wherein an amount ofchromium is in a range of from about 0.1 wt. % to about 5 wt. % basedupon the amount of silica, c) a titanium-containing compound wherein anamount of titanium is in a range of from about 0.1 wt. % to about 20 wt.% based upon the amount of silica, d) a carboxylic acid wherein anequivalent molar ratio of titanium-containing compound to carboxylicacid is in a range of from about 1:1 to about 1:10, and e) anitrogen-containing compound with a molecular formula containing atleast one nitrogen atom wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound is in arange of from about 1:0.5 to about 1:10.

Also disclosed herein is a pre-catalyst composition comprising a) asilica support comprising silica wherein an amount of silica is in arange of from about 70 wt. % to about 95 wt. % based upon a total weightof the silica support, b) a chromium-containing compound wherein anamount of chromium is in a range of from about 0.1 wt. % to about 5 wt.% based upon the amount of silica, and c) a titano-organic salt, whereinthe titano-organic salt comprises titanium, a protonatednitrogen-containing compound and a carboxylate, and wherein i) an amountof titanium is in a range of from about 0.1 wt. % to about 20 wt. %based upon the amount of silica, ii) an equivalent molar ratio oftitanium to carboxylate is in a range of from about 1:1 to about 1:10,and iii) an equivalent molar ratio of titanium to protonatednitrogen-containing compound is in a range of from about 1:0.5 to about1:10.

Also disclosed herein is a pre-catalyst composition comprising a) asilica support comprising silica wherein an amount of silica is in arange of from about 70 wt. % to about 95 wt. % based upon a total weightof the silica support, b) a chromium-containing compound wherein anamount of chromium is in a range of from about 0.1 wt. % to about 5 wt.% based upon the amount of silica, c) a titanium-containing compoundwherein an amount of titanium is in a range of from about 0.01 wt. % toabout 0.1 wt. % based upon the amount of silica, d) a carboxylic acidwherein an equivalent molar ratio of titanium-containing compound tocarboxylic acid is in a range of from about 1:1 to about 1:10, and e) anitrogen-containing compound with a molecular formula containing atleast one nitrogen atom wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound is in arange of from about 1:0.5 to about 1:10.

Also disclosed herein is a pre-catalyst composition prepared by a methodcomprising a) contacting a solvent and a carboxylic acid to form anacidic mixture wherein a weight ratio of solvent to carboxylic acid inthe acidic mixture is from about 1:1 to about 100:1, b) contacting atitanium-containing compound and the acidic mixture to form an acidictitanium mixture wherein an equivalent molar ratio oftitanium-containing compound to carboxylic acid in the acidic titaniummixture is from about 1:1 to about 1:4, c) contacting anitrogen-containing compound and the acidic titanium mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in thesolubilized titanium mixture is from about 1:1 to about 1:4 and a pH ofthe solubilized titanium mixture is less than about 5.5, and d)contacting a chromium-silica support comprising from about 0.1 wt. % toabout 20 wt. % water and the solubilized titanium mixture to form anaddition product and drying the addition product by heating the additionproduct to a temperature in a range of from about 50° C. to about 150°C. and maintaining the temperature of the addition product in the rangeof from about 50° C. to about 150° C. for a time period of from about 30minutes to about 6 hours to form the pre-catalyst.

Further disclosed herein is a method comprising a) contacting a solventand a carboxylic acid to form an acidic mixture wherein a weight ratioof solvent to carboxylic acid in the acidic mixture is from about 1:1 toabout 100:1, b) contacting a titanium-containing compound and the acidicmixture to form an acidic titanium mixture wherein an equivalent molarratio of titanium-containing compound to carboxylic acid in the acidictitanium mixture is from about 1:1 to about 1:4, c) contacting anitrogen-containing compound and the acidic titanium mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in thesolubilized titanium mixture is from about 1:1 to about 1:4 and a pH ofthe solubilized titanium mixture is less than about 5.5, and d)contacting a chromium-silica support comprising from about 0.1 wt. % toabout 20 wt. % water and the solubilized titanium mixture to form anaddition product and drying the addition product by heating the additionproduct to a temperature in a range of from about 50° C. to about 150°C. and maintaining the temperature of the addition product in the rangeof from about 50° C. to about 150° C. for a time period of from about 30minutes to about 6 hours to form a pre-catalyst.

Also disclosed herein is a method comprising a) contacting a solvent anda carboxylic acid to form an acidic mixture wherein a weight ratio ofsolvent to carboxylic acid in the acidic mixture is from about 1:1 toabout 100:1, b) contacting a titanium-containing compound and the acidicmixture to form an acidic titanium mixture wherein an equivalent molarratio of titanium-containing compound to carboxylic acid in the acidictitanium mixture is from about 1:1 to about 1:4, c) contacting anitrogen-containing compound and the acidic titanium mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in thesolubilized titanium mixture is from about 1:1 to about 1:4 and a pH ofthe solubilized titanium mixture is in a range of from about 3.5 toabout 4.5, d) contacting a silica support comprising from about 0.1 wt.% to about 20 wt. % water and the solubilized titanium mixture to form atitanated support and drying the titanated support by heating thetitanated support to a temperature in a range of from about 50° C. toabout 150° C. and maintaining the temperature of the titanated supportin the range of from about 50° C. to about 150° C. for a time period offrom about 30 minutes to about 6 hours to form a dried titanatedsupport, and e) contacting, to form a pre-catalyst, achromium-containing compound and at least one material selected from thegroup consisting of the silica support, the titanated support, and thedried titanated support.

Also disclosed herein is a method comprising a) contacting atitanium-containing compound and a nitrogen-containing compound to forma basic mixture wherein an equivalent molar ratio of titanium-containingcompound to nitrogen-containing compound in the basic mixture is fromabout 1:1 to about 1:4, b) contacting a solvent and a carboxylic acid toform an acidic mixture wherein a weight ratio of solvent to carboxylicacid in the acidic mixture is from about 1:1 to about 100:1, c)contacting the basic mixture and the acidic mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to carboxylic acid in the solubilizedtitanium mixture is from about 1:1 to about 1:4 and a pH of thesolubilized titanium mixture is in a range of from about 3.5 to about4.5, and d) contacting a chromium-silica support comprising from about0.1 wt. % to about 20 wt. % water and the solubilized titanium mixtureto form an addition product and drying the addition product by heatingthe addition product to a temperature in a range of from about 50° C. toabout 150° C. and maintaining the temperature of the addition product inthe range of from about 50° C. to about 150° C. for a time period offrom about 30 minutes to about 6 hours to form a pre-catalyst.

Also disclosed herein is a method comprising a) contacting atitanium-containing compound and a nitrogen-containing compound to forma basic mixture wherein an equivalent molar ratio of titanium-containingcompound to nitrogen-containing compound in the basic mixture is fromabout 1:1 to about 1:4, b) contacting a solvent and a carboxylic acid toform an acidic mixture wherein a weight ratio of solvent to carboxylicacid in the acidic mixture is from about 1:1 to about 100:1, c)contacting the basic mixture and the acidic mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to carboxylic acid in the solubilizedtitanium mixture is from about 1:1 to about 1:4 and a pH of thesolubilized titanium mixture is in a range of from about 3.5 to about4.5, d) contacting a silica support comprising from about 0.1 wt. % toabout 20 wt. % water and the solubilized titanium mixture to form atitanated support and drying the titanated support by heating thetitanated support to a temperature in a range of from about 50° C. toabout 150° C. and maintaining the temperature of the titanated supportin the range of from about 50° C. to about 150° C. for a time period offrom about 30 minutes to about 6 hours to form a dried titanatedsupport, and e) contacting, to form a pre-catalyst, achromium-containing compound and at least one material selected from thegroup consisting of the silica support, the titanated support, and thedried titanated support.

BRIEF DESCRIPTION OF THE FIGURE

The following FIGURE forms part of the present specification and isincluded to further demonstrate certain aspects of the presentdisclosure. The subject matter of the present disclosure may be betterunderstood by reference to the FIGURE in combination with the detaileddescription of specific aspects presented herein.

The FIGURE illustrates relationships between zeta potential and pH valuefor silica and titania.

While the subject matter disclosed herein is susceptible to variousmodifications and alternative forms, only a few specific aspects havebeen shown by way of example in the drawing and are described below indetail. The FIGURE and detailed descriptions of these specific aspectsare not intended to limit the breadth or scope of the subject matterdisclosed or the appended claims in any manner. Rather, the FIGURE anddetailed written descriptions are provided to illustrate the presentdisclosure to a person skilled in the art and to enable such person tomake and use the concepts disclosed herein.

DETAILED DESCRIPTION

The present disclosure encompasses olefin polymerization catalysts andpre-catalysts thereof, methods of preparing olefin polymerizationcatalysts and pre-catalysts thereof, and methods of utilizing olefinpolymerization catalysts. In an aspect, a method of the presentdisclosure comprises contacting a silica support or a chromium-silicasupport (i.e., support) with titanium to produce a Cr/Si—Ti catalyst.The methodologies disclosed herein contemplate the use of a solubilizedtitanium mixture (STM) to facilitate the association of titanium withthe support in the presence of water. Herein a methodology forpreparation of the olefin polymerization catalyst comprises contactingthe chromium-silica support with the STM under conditions suitable toform the catalyst composition. An alternative methodology forpreparation of the olefin polymerization catalyst comprises contactingthe silica support with the STM and chromium under conditions suitableto form a catalyst composition. While these aspects may be disclosedunder a particular heading, the heading does not limit the disclosurefound therein. Additionally, the various aspects and embodimentsdisclosed herein can be combined in any manner.

Aspects of the present disclosure are directed to catalyst compositionsand pre-catalyst compositions. In an aspect, a catalyst compositioncomprises an olefin polymerization catalyst. In a further aspect, theolefin polymerization catalyst comprises a treated pre-catalystcomposition. In yet a further aspect, the treated pre-catalystcomposition comprises a pre-catalyst that has been subjected to anactivation treatment (e.g., calcination) as disclosed herein.

Disclosed herein are pre-catalyst compositions. In an aspect, apre-catalyst composition comprises a silica support, achromium-containing compound, a titanium-containing compound, acarboxylic acid, and a nitrogen-containing compound. Alternatively, thepre-catalyst composition comprises the silica support, thechromium-containing compound, and a titano-organic salt.

In an aspect, an olefin polymerization catalyst and a pre-catalystthereof of the present disclosure comprise a silica support. The silicasupport may be any silica support suitable for preparation of the olefinpolymerization catalyst and the pre-catalyst thereof as disclosedherein. In a further aspect, preparation of the olefin polymerizationcatalyst and the pre-catalyst thereof excludes thermal treatment of thesilica support prior to contact with any other catalyst component.Consequently, the silica support suitable for use in the presentdisclosure may be a termed a hydrated silica support. Without wishing tobe limited by theory, the hydrated silica support comprises a silicasupport wherein water evolution occurs when the silica support is heatedwithin a range of from about 180° C. to about 200° C. under vacuumconditions for a period of time ranging from about 8 hours to about 20hours. In a further aspect, the silica support may contain from about0.1 wt. % to about 20 wt. % water; alternatively, about 1 wt. % to about20 wt. % water; alternatively, about 1 wt. % to about 10 wt. % water; oralternatively, about 0.1 wt. % to about 10 wt. % water based upon thetotal weight of the silica support.

The silica support suitable for use in the present disclosure may have asurface area and a pore volume effective to provide for the productionof an active olefin polymerization catalyst. In an aspect of the presentdisclosure, the silica support possesses a surface area in a range offrom about 100 m²/gram to about 1000 m²/gram; alternatively, from about250 m²/gram to about 1000 m²/gram; alternatively, from about 250 m²/gramto about 700 m²/gram; alternatively, from about 250 m²/gram to about 600m²/gram; or alternatively, greater than about 250 m²/gram. The silicasupport may be further characterized by a pore volume of greater thanabout 0.9 cm³/gram; alternatively, greater than about 1.0 cm³/gram; oralternatively, greater than about 1.5 cm³/gram. In an aspect of thepresent disclosure, the silica support is characterized by a pore volumein a range of from about 1.0 cm³/gram to about 2.5 cm³/gram. The silicasupport may be further characterized by an average particle size in arange of from about 10 microns to about 500 microns; alternatively,about 25 microns to about 300 microns; or alternatively, about 40microns to about 150 microns. Generally, an average pore size of thesilica support may be in a range of from about 10 Angstroms to about1000 Angstroms. In one aspect of the present disclosure, the averagepore size of the silica support is in a range of from about 50 Angstromsto about 500 Angstroms; alternatively, from about 75 Angstroms to about350 Angstroms.

The silica support suitable for use in the present disclosure maycontain greater than about 50 wt. % silica; alternatively, greater thanabout 80 wt. % silica; or alternatively, greater than about 95 wt. %silica based upon the total weight of the silica support. In an aspect,the silica support comprises an amount of silica in a range of fromabout 70 wt. % to about 95 wt. % based upon a total weight of the silicasupport. The silica support may be prepared using any suitable method,e.g., the silica support may be prepared by hydrolyzingtetrachlorosilane (SiC1₄) with water or by contacting sodium silicateand a mineral acid. In a particular aspect, the silica support may be ahydrogel or a preformed silica support wherein the preformed silicasupport optionally has been dried prior to contact with any othercatalyst component. The silica support may include additional componentsthat do not adversely affect the catalyst, such as zirconia, alumina,thoria, magnesia, fluoride, sulfate, phosphate, or a combinationthereof. In a particular aspect, the silica support of the presentdisclosure comprises alumina. Non-limiting examples of silica supportssuitable for use in this disclosure include ES70, which is a silicasupport material with a surface area of 300 m²/gram and a pore volume of1.6 cm³/gram, that is commercially available from PQ Corporation andV398400, which is a silica support material that is commerciallyavailable from Evonik.

In a particular aspect of the present disclosure, a silica supportsuitable for use in the present disclosure comprises chromium. Thesilica support comprising chromium may be termed a chrominated silicasupport or a chromium-silica support. In another aspect, thechromium-silica support comprises the characteristics disclosed hereinfor the silica support while additionally containing chromium. Anon-limiting example of the chrominated silica support is HW30A, whichis a chromium-silica support material that is commercially availablefrom W. R. Grace and Company.

The silica support may be present in the olefin polymerization catalystand a pre-catalyst thereof in an amount in a range of from about 50 wt.% to about 99 wt. %; or alternatively, from about 80 wt. % to about 99wt. %. Herein a silica support percentage refers to a weight percent(wt. %) of the silica support associated with the olefin polymerizationcatalyst based upon the total weight of the olefin polymerizationcatalyst after completion of all processing steps (i.e., afteractivation via calcination). Alternatively, the silica supportpercentage refers to a weight percent (wt. %) of the silica supportassociated with the pre-catalyst based upon the total weight of thepre-catalyst after completion of all relevant processing steps excludingactivation via calcination.

In a still further aspect, an olefin polymerization catalyst and apre-catalyst thereof of the present disclosure comprise chromium. Thesource of chromium may be any chromium-containing compound capable ofproviding a sufficient amount of chromium to the olefin polymerizationcatalyst and the pre-catalyst thereof. In an aspect, thechromium-containing compound may be a water-soluble chromium compound ora hydrocarbon-soluble chromium compound. Examples of water-solublechromium compounds include chromium trioxide, chromium acetate, chromiumnitrate, or a combination thereof. Examples of hydrocarbon-solublechromium compounds include tertiary butyl chromate, biscyclopentadienylchromium(II), chromium(III) acetylacetonate, or a combination thereof.In one aspect of the present disclosure, the chromium-containingcompound may be a chromium(II) compound, a chromium(III) compound, or acombination thereof. Suitable chromium(III) compounds include, but arenot limited to, chromium(III) carboxylates, chromium(III) naphthenates,chromium(III) halides, chromium(III) sulfates, chromium(III) nitrates,chromium(III) dionates, or a combination thereof. Specific chromium(III)compounds include, but are not limited to, chromium(III) sulfate,chromium(III) chloride, chromium(III) nitrate, chromium(III) bromide,chromium(III) acetylacetonate, and chromium(III) acetate. Suitablechromium(II) compounds include, but are not limited to, chromium(II)chloride, chromium(II) bromide, chromium(II) iodide, chromium(II)sulfate, chromium(II) acetate, or a combination thereof.

An amount of chromium present in the olefin polymerization catalyst maybe in a range of from about 0.01 wt. % to about 10 wt. %; alternatively,from about 0.5 wt. % to about 5 wt. %; alternatively, from about 1 wt. %to about 4 wt. %; or alternatively, from about 2 wt. % to about 4 wt. %chromium based upon the total weight of the olefin polymerizationcatalyst. In another aspect, the amount of chromium present in theolefin polymerization catalyst may be in a range of from about 1 wt. %to about 5 wt. % chromium based upon the total weight of the olefinpolymerization catalyst. Herein, a chromium percentage refers to aweight percent (wt. %) of chromium associated with the olefinpolymerization catalyst based upon the total weight of the olefinpolymerization catalyst after completion of all processing steps (i.e.,after activation via calcination). In a further aspect, an amount ofchromium present in a pre-catalyst may be in a range of from about 0.01wt. % to about 10 wt. %; alternatively, from about 0.1 wt. % to about 5wt. %; alternatively, from about 0.2 wt. % to about 2 wt. %; oralternatively, from about 0.5 wt. % to about 1.5 wt. % chromium basedupon a total weight of silica within the pre-catalyst. Herein, achromium percentage refers to a weight percent (wt. %) of chromiumassociated with the pre-catalyst based upon the total weight of silicawithin the pre-catalyst after completion of all processing stepsexcluding activation via calcination.

In a further aspect, an olefin polymerization catalyst and apre-catalyst thereof of the present disclosure comprise titanium. Thesource of titanium may be any titanium-containing compound capable ofproviding a sufficient amount of titanium to the olefin polymerizationcatalyst and the pre-catalyst thereof. In a further aspect, thetitanium-containing compound comprises a tetravalent titanium (Ti(IV))compound or a trivalent titanium (Ti(III)) compound. The Ti(IV) compoundmay be any compound that comprises Ti(IV); alternatively, the Ti(IV)compound may be any compound that is able to release a Ti(IV) speciesupon dissolving into solution. The Ti(III) compound may be any compoundthat comprises Ti(III); alternatively, the Ti(III) compound may be anycompound that is able to release a Ti(III) species upon dissolving intosolution.

In an aspect, the titanium-containing compound suitable for use in thepresent disclosure comprises a Ti(IV) compound having at least onealkoxide group; or alternatively, at least two alkoxide groups. Ti(IV)compounds suitable for use in the present disclosure include, but arenot limited to, Ti(IV) compounds that have the general formulaTiO(OR^(K))₂, Ti(OR^(K))₂(acac)₂, Ti(OR^(K))₂(oxal), a combinationthereof wherein R^(K) may be ethyl, isopropyl, n-propyl, isobutyl,n-butyl, or a combination thereof; “acac” is acetylacetonate; and “oxal”is oxalate. Alternatively, the titanium-containing compound comprises atitanium(IV) alkoxide. In an aspect, the titanium(IV) alkoxide may betitanium(IV) ethoxide, titanium(IV) isopropoxide, titanium(IV)n-propoxide, titanium(IV) n-butoxide, titanium(IV) 2-ethylhexoxide, or acombination thereof. In a particular aspect, the titanium-containingcompound may be titanium(IV) isopropoxide.

In a still further aspect, the titanium-containing compound suitable foruse in the present disclosure may comprise hydrous titania, titaniumhydroxide, titanic acid, titanyl sulfate, titanium acetylacetonate,titanium oxyacetylacetonate, or a combination thereof.

In yet another aspect, the titanium-containing compound suitable for usein the present disclosure may comprise a titanium(IV) halide,non-limiting examples of which include titanium tetrachloride, titaniumtetrabromide, titanium (IV) oxychloride, and titanium(IV) oxybromide. Ina further aspect the titanium(IV) halide may comprise a titaniumalkoxyhalide having the general formula Ti(OR^(K))_(n)Q_(4-n); whereinR^(K) may be ethyl, isopropyl, n-propyl, isobutyl, n-butyl, or acombination thereof; wherein Q may be a fluoride, a chloride, a bromide,an iodide, or a combination thereof; and wherein n may be an integerfrom 1 to 4.

An amount of titanium present in an olefin polymerization catalyst ofthe present disclosure may range from about 0.01 wt. % to about 10 wt.%; alternatively, from about 0.5 wt. % to about 5 wt. %; alternatively,from about 1 wt. % to about 4 wt. %; or alternatively, from about 2 wt.% to about 4 wt. % titanium based upon the total weight of the olefinpolymerization catalyst. In another aspect, the amount of titaniumpresent in the olefin polymerization catalyst may range from about 1 wt.% to about 5 wt. % titanium based upon the total weight of the olefinpolymerization catalyst. Herein, a titanium percentage refers to aweight percent (wt. %) of titanium associated with the olefinpolymerization catalyst based upon the total weight of the olefinpolymerization catalyst after completion of all processing steps (i.e.,after activation via calcination). In a further aspect, an amount oftitanium present in a pre-catalyst of the present disclosure may rangefrom about 0.01 wt. % to about 25 wt. %; alternatively, from about 0.1wt. % to about 20 wt. %; alternatively, from about 0.5 wt. % to about 10wt. %; alternatively, from about 1 wt. % to about 6 wt. %; oralternatively, from about 2 wt. % to about 4 wt. % titanium based upon atotal weight of silica within the pre-catalyst. Herein, a titaniumpercentage refers to a weight percent (wt. %) of titanium associatedwith the pre-catalyst based upon a total weight of silica within thepre-catalyst after completion of all processing steps excludingactivation via calcination.

In an aspect, an olefin polymerization catalyst and a pre-catalystthereof of the present disclosure comprise a carboxylic acid. Thecarboxylic acid may be a monocarboxylic acid, a dicarboxylic acid, atricarboxylic acid, an α-hydroxycarboxylic acid, a β-hydroxycarboxylicacid, an α-ketocarboxylic acid, or a combination thereof. In an aspect,the carboxylic acid may be a C₁ to C₁₅ monocarboxylic acid or a C₁ to C₅monocarboxylic acid; alternatively, a C₁ to C₁₅ dicarboxylic acid or aC₁ to C₅ dicarboxylic acid; alternatively, a C₁ to C₁₅ tricarboxylicacid or a C₁ to C₅ tricarboxylic acid; alternatively, a C₁ to C₁₅α-hydroxycarboxylic acid or a C₁ to C₅ α-hydroxycarboxylic acid;alternatively, a C₁ to C₁₅ β-hydroxycarboxylic acid or a C₁ to C₅β-hydroxycarboxylic acid; or alternatively, a C₁ to C₁₅ α-ketocarboxylicacid or a C₁ to C₅ α-ketocarboxylic acid.

In a particular aspect, the carboxylic acid may be acetic acid, citricacid, gluconic acid, glycolic acid, glyoxylic acid, lactic acid, malicacid, malonic acid, oxalic acid, phosphonoacetic acid, tartaric acid, ora combination thereof. In yet a further aspect, the carboxylic acid maybe oxalic acid.

A pre-catalyst of the present disclosure comprises an equivalent molarratio of titanium to carboxylic acid in a range of from about 1:1 toabout 1:10; alternatively, from about 1:1 to about 1:5 or alternatively,from about 1:1.5 to about 1:4. In an aspect, the equivalent molar ratioof titanium to carboxylic acid is in a range of from about 1:1 to about1:2.

In an aspect, an olefin polymerization catalyst and a pre-catalystthereof of the present disclosure comprise a nitrogen-containingcompound. The nitrogen-containing compound may be anynitrogen-containing compound suitable for providing effective titanationof the olefin polymerization catalyst and the pre-catalyst thereof. In afurther aspect, the nitrogen-containing compound may have Structure 1,Structure 2, Structure 3, Structure 4, Structure 5, Structure 6, or acombination thereof.

R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, and R¹² within thenitrogen-containing compound utilized as described herein areindependent elements of the nitrogen-containing compound structure inwhich they are present and are independently described herein. Theindependent descriptions of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰,R¹¹, and/or R¹² provided herein can be utilized without limitation, andin any combination, to further describe any nitrogen-containing compoundstructure which comprises an R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰,R¹¹, and R¹².

Generally, R¹, R², R³, R⁵, R⁶, R⁹, R¹⁰, and/or R¹¹ of a respectivenitrogen-containing compound which has an R¹, R², R³, R⁵, R⁶, R⁹, R¹⁰,and/or R¹¹ may each independently be hydrogen, an organyl group, ahydrocarbyl group, or an aryl group. In an aspect, R¹, R², R³, R⁵, R⁶,R⁹, R¹⁰, and/or R¹¹ may each independently be a C₁ to C₃₀ organyl group;alternatively, a C₁ to C₁₂ organyl group; or alternatively, a C₁ to C₆organyl group. In an aspect, R¹, R², R³, R⁵, R⁶, R⁹, R¹⁰, and/or R¹¹ mayeach independently be a C₁ to C₃₀ hydrocarbyl group; alternatively, a C₁to C₁₂ hydrocarbyl group; or alternatively, a C₁ to C₆ hydrocarbylgroup. In yet other aspects, R¹, R², R³, R⁵, R⁶, R⁹, R¹⁰, and/or R¹¹ mayeach independently be a C₆ to C₃₀ aryl group; or alternatively, a C₆ toC₁₂ aryl group. In a further aspect, any organyl group, hydrocarbylgroup or aryl group which may be used as R¹, R², R³, R⁵, R⁶, R⁹, R¹⁰,and/or R¹¹ within the nitrogen-containing compound of the presentdisclosure may be substituted or non-substituted. It will be understoodby one skilled in the art that the terms “alkyl”, “organyl”,“hydrocarbyl”, and “aryl” are used herein in accordance with thedefinitions from the IUPAC Compendium of Chemical Terminology, 2^(nd) Ed(1997).

R⁴ of a respective nitrogen-containing compound which has an R⁴ may bean organyl group, a hydrocarbyl group or an aryl group. In an aspect, R⁴may be a C₁ to C₃₀ organyl group; alternatively, a C₁ to C₁₂ organylgroup; or alternatively, a C₁ to C₆ organyl group. In an aspect, R⁴ maybe a C₁ to C₃₀ hydrocarbyl group; alternatively, a C₁ to C₁₂ hydrocarbylgroup; or alternatively, a C₁ to C₆ hydrocarbyl group. In yet otheraspects, R⁴ may be a C₆ to C₃₀ aryl group; or alternatively, a C₆ to C₁₂aryl group. In a further aspect, any organyl group, hydrocarbyl group oraryl group which may be used as R⁴ within the nitrogen-containingcompound of the present disclosure may be substituted ornon-substituted.

In a particular aspect, any substituted organyl group, substitutedhydrocarbyl group or substituted aryl group which may be used as R¹, R²,R³, R⁴, R⁵, R⁶, R⁹, R¹⁰, and/or R¹¹ may contain one or more non-hydrogensubstituents. The non-hydrogen substituents suitable for use herein maybe a halogen, a C₁ to C₁₂ hydrocarbyl group, a C₁ to C₁₂ hydrocarboxygroup, or a combination thereof. In an aspect, the halogen utilized asthe non-hydrogen substituent may be fluorine, chlorine, bromine, oriodine. Non-limiting examples of the C₁ to C₁₂ hydrocarboxy groupsuitable for use herein include a methoxy group, an ethoxy group, apropoxy group, a butoxy group, a pentoxy group, a hexoxy group, aphenoxy group, a toloxy group, a xyloxy group, a trimethylphenoxy group,and a benzoxy group.

R⁷ and/or R⁸ of a respective nitrogen-containing compound which has anR⁷ and/or R⁸ may each independently be hydrogen or a methyl group.

R¹² of a respective nitrogen-containing compound which has an R¹² may bea branched alkyl group or a linear alkyl group. In an aspect, R¹² may bea C₁ to C₃₀ branched alkyl group; alternatively, a C₁ to C₁₂ branchedalkyl group; or alternatively, a C₁ to C₆ branched alkyl group. In afurther aspect, R¹² may be a C₁ to C₃₀ linear alkyl group;alternatively, a C₁ to C₁₂ linear alkyl group; or alternatively, a C₁ toC₆ linear alkyl group.

In still another aspect, a nitrogen-containing compound of the presentdisclosure which has Structure 2 may have x wherein x is an integer from1 to 4. In an aspect, the nitrogen-containing compound which hasStructure 3 may have y wherein y is an integer from 1 to 12. In yet afurther aspect, the nitrogen-containing compound which has Structure 5may have Z wherein Z is oxygen or sulfur.

In an aspect, a nitrogen-containing compound suitable for use in thepresent disclosure may be an alkanolamine, an amide, an amine, analkylamine, an ammonium hydroxide, an aniline, a hydrazide, ahydroxylamine, an imine, a urea, or a combination thereof. In a furtheraspect, the alkanolamine, the amide, the amine, the ammonium hydroxide,the hydrazide, the hydroxylamine, the imine, and/or the urea used as thenitrogen-containing compound may contain one or more substituent groups.In an aspect, any substituent group contained within anynitrogen-containing compound of the present disclosure may be a halogen,a C₁ to C₁₂ organyl group, a C₁ to C₁₂ hydrocarbyl group, a C₁ to C₁₂hydrocarboxy group, or a combination thereof. The halogen utilized asthe substituent group of any aspect disclosed herein may be fluorine,chlorine, bromine, or iodine. Non-limiting examples of the C₁ to C₁₂hydrocarboxy group suitable for use herein include a methoxy group, anethoxy group, a propoxy group, a butoxy group, a pentoxy group, a hexoxygroup, a phenoxy group, a toloxy group, a xyloxy group, atrimethylphenoxy group, and a benzoxy group.

In a still further aspect, non-limiting examples of specificnitrogen-containing compounds suitable for use in the present disclosureinclude acetamide, acryl amide, allyl amine, ammonia, ammoniumhydroxide, butyl amine, tert-butyl amine, N,N′-dibutyl urea, creatine,creatinine, diethanol amine, diethylhydroxy amine, diisopropanol amine,dimethylaminoethanol, dimethyl carbamate, dimethyl formamide, dimethylglycine, dimethylisopropanol amine, N,N′-dimethyl urea, ethanol amine,ethyl amine, glycol amine, hexyl amine, hydroxyamine, imidazole,isopropanol amine, methacryl amide, methyl amine, N-methyl aniline,N-methyl-2-propanol amine, methyldiethanol amine, methyl formamide,propyl amine, 2-propanol amine, pyrazole, pyrrolidine, pyrrolidinone,succinimide, tetraethylammonium hydroxide, tetramethylammoniumhydroxide, triethanol amine, triisopropanol amine, trimethyl amine,urea, 1,8-diazabicyclo[5.4.0]undec-7-ene, or a combination thereof.

A pre-catalyst of the present disclosure comprises an equivalent molarratio of titanium to nitrogen-containing compound in a range of fromabout 2:1 to about 1:10; alternatively, from about 1:1 to about 1:5; oralternatively, from about 1:1.5 to about 1:4. In an aspect, theequivalent molar ratio of titanium to nitrogen-containing compound is ina range of from about 1:1 to about 1:2.

In a particular aspect, a pre-catalyst composition of the presentdisclosure comprises a titano-organic salt. In an aspect, thepre-catalyst composition comprising the titano-organic salt furthercomprises a silica support and a chromium-containing compound, both ofthe type previously disclosed herein. In a further aspect, thetitano-organic salt suitable for use herein comprises titanium, aprotonated nitrogen-containing compound, and a carboxylate.

In an aspect, the titano-organic salt comprises titanium. The source oftitanium may be any titanium-containing compound capable of providing asufficient amount of titanium to a pre-catalyst as disclosed herein. Ina further aspect, the source of titanium is a titanium-containingcompound of the type previously disclosed herein.

In an aspect, the titano-organic salt comprises a protonatednitrogen-containing compound titanium. The protonatednitrogen-containing compound may be any protonated nitrogen-containingcompound capable of providing a sufficient amount of titanium to apre-catalyst as disclosed herein. In a further aspect, the protonatednitrogen-containing compound may comprise a protonated form of anynitrogen-containing compound of the type previously disclosed herein.

In an aspect, the protonated nitrogen-containing compound comprises aprotonated alkanolamine, a protonated amide, a protonated amine, aprotonated alkylamine, a protonated ammonium hydroxide, a protonatedaniline, a protonated hydroxylamine, a protonated urea, or a combinationthereof.

In yet a further aspect, the protonated nitrogen-containing compoundcomprises protonated acetamide, protonated acryl amide, protonated allylamine, ammonium, protonated ammonium hydroxide, protonated butyl amine,protonated tert-butyl amine, protonated N,N′-dibutyl urea, protonatedcreatine, protonated creatinine, protonated diethanol amine, protonateddiethylhydroxy amine, protonated diisopropanol amine, protonateddimethylaminoethanol, protonated dimethyl carbamate, protonated dimethylformamide, protonated dimethyl glycine, protonated dimethylisopropanolamine, protonated N,N′-dimethyl urea, protonated ethanol amine,protonated ethyl amine, protonated glycol amine, protonated hexyl amine,protonated hydroxyamine, protonated imidazole, protonated isopropanolamine, protonated methacryl amide, protonated methyl amine, protonatedN-methyl aniline, protonated N-methyl-2-propanol amine, protonatedmethyldiethanol amine, protonated methyl formamide, protonated propylamine, protonated 2-propanol amine, protonated pyrazole, protonatedpyrrolidine, protonated pyrrolidinone, protonated succinimide,protonated tetraethylammonium hydroxide, protonated tetramethylammoniumhydroxide, protonated triethanol amine, protonated triisopropanol amine,protonated trimethyl amine, protonated urea, protonated1,8-diazabicyclo[5.4.0]undec-7-ene, or a combination thereof.

In a still further aspect, the titano-organic salt comprises acarboxylate. The carboxylate may be any carboxylate capable of providinga sufficient amount of titanium to a pre-catalyst as disclosed herein.In an aspect, the carboxylate may comprise an anionic form of anycarboxylic acid of the type previously disclosed herein.

In a further aspect, the carboxylate comprises a C₁ to C₁₅monocarboxylate, a C₁ to C₁₅ dicarboxylate, a C₁ to C₁₅ tricarboxylate,a C₁ to C₁₅ α-hydroxycarboxylate, or a combination thereof.

In a still further aspect, the carboxylate comprises acetate, citrate,gluconate, glycolate, glyoxylate, lactate, malate, malonate, oxalate,phosphonoacetate, tartrate, or a combination thereof.

In a further aspect, an amount of titanium present in the titano-organicsalt of the present disclosure may range from about 0.01 wt. % to about20 wt. %; alternatively, from about 0.5 wt. % to about 10 wt. %; oralternatively, from about 1 wt. % to about 6 wt. % titanium based upon atotal weight of silica of a pre-catalyst as disclosed herein. In anotheraspect, the titano-organic salt comprises an equivalent molar ratio oftitanium to carboxylate in a range of from about 1:1 to about 1:10;alternatively, from about 1:1 to about 1:5 or alternatively, from about1:1.5 to about 1:4. In some aspects, the equivalent molar ratio oftitanium to carboxylate may be about 1:2. In yet another aspect, thetitano-organic salt comprises an equivalent molar ratio of titanium tonitrogen-containing compound in a range of from about 2:1 to about 1:10;alternatively, from about 1:1 to about 1:5; or alternatively, from about1:1.5 to about 1:4. In a still further aspect, the equivalent molarratio of titanium to nitrogen-containing compound may be about 1:2.

In an aspect of the present disclosure, a method for preparation of anolefin polymerization catalyst comprises utilization of a solubilizedtitanium mixture (STM). In a particular aspect, the STM of the presentdisclosure comprises a carboxylic acid, a titanium-containing compound,a nitrogen-containing compound, and a solvent. In an aspect, the STMcomprises a carboxylic acid of the type used as a component of apre-catalyst as disclosed herein. In a further aspect, the STM comprisesa titanium-containing compound of the type used as a component of thepre-catalyst as disclosed herein. In a further aspect, the STM comprisesa nitrogen-containing compound of the type used as a component of thepre-catalyst as disclosed herein.

In a further aspect, the STM of the present disclosure comprises asolvent. The solvent may be an aqueous solvent, an alcohol, an organicsolvent, a hydrocarbon, or a combination thereof. A non-limiting exampleof an aqueous solvent suitable for use in the present disclosurecomprises deionized water, distilled water, filtered water, or acombination thereof. Non-limiting examples of alcohols suitable for useas the solvent include methanol, ethanol, n-propanol, isopropanol,n-butanol, isobutanol, pentanol, hexanol, cyclohexanol, heptanol,octanol, benzyl alcohol, phenol, or a combination thereof. In a furtheraspect, the organic solvent suitable for use in the present disclosuremay be an ester, a ketone, or a combination thereof. Non-limitingexamples of esters suitable for use as the solvent include ethylacetate, propyl acetate, butyl acetate, isobutyl isobutyrate, methyllactate, ethyl lactate, or a combination thereof. Non-limiting examplesof ketones suitable for use as the solvent include acetone, ethyl methylketone, methyl isobutyl ketone, or a combination thereof. In aparticular aspect, the hydrocarbon suitable for use as the solvent maybe a halogenated aliphatic hydrocarbon, an aromatic hydrocarbon, ahalogenated aromatic hydrocarbon, or a combination thereof. Non-limitingexamples of the hydrocarbon suitable for use as the solvent includemethylene chloride, chloroform, carbon tetrachloride, dichloroethane,trichloroethane, benzene, toluene, ethylbenzene, xylenes, chlorobenzene,dichlorobenzene, or a combination thereof.

In a particular aspect, a solubilized titanium mixture (STM) asdisclosed herein comprises an acidic mixture that may be prepared bycontacting a carboxylic acid and a solvent. In an aspect, the STM isprepared by sequential addition of a titanium-containing compoundfollowed by a nitrogen-containing compound to the acidic mixture asdisclosed herein. In an alternative aspect, the titanium-containingcompound and the nitrogen-containing compound may be contacted to form abasic mixture that is subsequently contacted with the acidic mixture toform the STM as disclosed herein. In a further aspect, thenitrogen-containing compound utilized to form the basic mixture may be acomponent of an aqueous solution.

In an aspect, a solubilized titanium mixture (STM) of the presentdisclosure comprises an acidic mixture having a weight ratio of solventto carboxylic acid in a range of from about 1:1 to about 100:1;alternatively, from about 1:1 to about 50:1; or alternatively, fromabout 1:1 to about 10:1. In a further aspect, the STM comprises anequivalent molar ratio of titanium-containing compound to carboxylicacid in a range of from about 1:1 to about 1:20; alternatively, fromabout 1:1 to about 1:10; or alternatively, from about 1:1 to about 1:4.In some aspects, the equivalent molar ratio of titanium-containingcompound to carboxylic acid may be about 1:2. In another aspect, the STMcomprises an equivalent molar ratio of nitrogen-containing compound tocarboxylic acid in a range of from about 1:5 to about 5:1;alternatively, from about 0.5:1 to about 3:1; alternatively, from about0.5:1 to about 1.5:1; or alternatively, from about 1.5:1 to about 2.5:1.

In yet a further aspect, the STM comprises an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in a rangeof from about 1:5 to about 5:1; alternatively, from about 1:4 to about2:1; alternatively, from about 1:3 to about 1:1; or alternatively, fromabout 0.4:1 to about 0.67:1. In still further aspects, the equivalentmolar ratio of titanium-containing compound to nitrogen-containingcompound may be about 1:2.

In a particular aspect, the STM suitable for use in the presentdisclosure may be characterized by a pH of less than about 5.5.Alternatively, the STM may be characterized by a pH in a range of fromabout 2.5 to about 5.5; alternatively, from about 3.0 to about 5.0; oralternatively, from about 3.5 to about 4.5.

In an aspect of the present disclosure the catalyst components disclosedherein may be contacted in any order or fashion deemed suitable to oneof ordinary skill in the art with the aid of the present disclosure toproduce an olefin polymerization catalyst having the characteristicsdisclosed herein.

In a particular aspect, a method for preparation of an olefinpolymerization catalyst comprises contacting a solvent and a carboxylicacid, both of the type disclosed herein, to form an acidic mixture. Themethod may further comprise contacting a titanium-containing compound ofthe type disclosed herein and the acidic mixture to form an acidictitanium mixture. In an aspect, a nitrogen-containing compound of thetype disclosed herein and the acidic titanium mixture may be contactedto form a solubilized titanium mixture (STM) as disclosed herein, e.g.,the nitrogen-containing compound may be added to the acidic titaniummixture to form the STM. In some aspects, the nitrogen-containingcompound is added to the acidic titanium mixture as a single portion ofan amount sufficient to form an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound of about1:2 within the STM. In a particular aspect, an amount ofnitrogen-containing compound to be added to the acidic titanium mixtureis determined with an acid-base indicator, (e.g., bromocresol green),wherein the nitrogen-containing compound is added to the acidic titaniummixture in multiple portions and wherein a single portion comprises fromabout 3% to about 10% of the amount of nitrogen-containing compound thatcomprises an equivalent molar ratio of titanium-containing compound tonitrogen-containing compound of about 1:2. Addition of the multipleportions of the nitrogen-containing compound may be ceased when agreen-hued endpoint of a bromocresol green indicator is achieved. Insome aspects, the green-hued endpoint of the bromocresol green indicatorcorrelates to a pH value within the STM of about 4.0. In a furtheraspect, addition of the nitrogen-containing compound to the acidictitanium mixture comprises neutralizing the acidic titanium mixturepartially; or alternatively, neutralizing the acidic titanium mixturecompletely. The method for preparation of the olefin polymerizationcatalyst may further comprise contacting a chromium-silica support ofthe type disclosed herein and the STM to form an addition product. In afurther aspect, the addition product may be dried by heating theaddition product to a temperature in a range of from about 25° C. toabout 300° C.; alternatively, from about 50° C. to about 150° C.; oralternatively, from about 75° C. to about 100° C. The method furthercomprises maintaining the temperature of the addition product in therange of from about 25° C. to about 300° C.; alternatively, from about50° C. to about 150° C.; or alternatively, from about 75° C. to about100° C. for a time period of from about 30 minutes to about 6 hours toform a pre-catalyst.

In a further aspect, a method for preparation of an olefinpolymerization catalyst comprises contacting a solvent and a carboxylicacid, both of the type disclosed herein, to form an acidic mixture. Themethod may further comprise contacting a titanium-containing compound ofthe type disclosed herein and the acidic mixture to form an acidictitanium mixture. In an aspect, a nitrogen-containing compound of thetype disclosed herein and the acidic titanium mixture may be contactedto form a solubilized titanium mixture (STM) as disclosed herein, e.g.,the nitrogen-containing compound may be added to the acidic titaniummixture to form the STM. In some aspects, the nitrogen-containingcompound is added to the acidic titanium mixture as a single portion ofan amount sufficient to form an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound of about1:2 within the STM. In a particular aspect, an amount ofnitrogen-containing compound to be added to the acidic titanium mixtureis determined with an acid-base indicator, (e.g., bromocresol green),wherein the nitrogen-containing compound is added to the acidic titaniummixture in multiple portions and wherein a single portion comprises fromabout 3% to about 10% of the amount of nitrogen-containing compound thatcomprises an equivalent molar ratio of titanium-containing compound tonitrogen-containing compound of about 1:2. Addition of the multipleportions of the nitrogen-containing compound may be ceased when agreen-hued endpoint of a bromocresol green indicator is achieved. Insome aspects, the green-hued endpoint of the bromocresol green indicatorcorrelates to a pH value within the STM of about 4.0. In a furtheraspect, addition of the nitrogen-containing compound to the acidictitanium mixture comprises neutralizing the acidic titanium mixturepartially; or alternatively, neutralizing the acidic titanium mixturecompletely. The method for preparation of the olefin polymerizationcatalyst may further comprise contacting a silica support of the typedisclosed herein and the STM to form a titanated support. In a furtheraspect, the titanated support may be dried by heating the titanatedsupport to a temperature in a range of from about 25° C. to about 300°C.; alternatively, from about 50° C. to about 150° C.; or alternatively,from about 75° C. to about 100° C. The method further comprisesmaintaining the temperature of the titanated support in the range offrom 25° C. to about 300° C.; alternatively, from about 50° C. to about150° C.; or alternatively, from about 75° C. to about 100° C. for a timeperiod of from about 30 minutes to about 6 hours to form a driedtitanated support. The method may further comprise contacting achromium-containing compound of the type disclosed herein and the driedtitanated support to form an addition product that may be dried byheating the addition product to a temperature in a range of from about25° C. to about 300° C.; alternatively, from about 50° C. to about 150°C.; or alternatively, from about 75° C. to about 100° C. The methodfurther comprises maintaining the temperature of the addition product inthe range of from about 25° C. to about 300° C.; alternatively, fromabout 50° C. to about 150° C.; or alternatively, from about 75° C. toabout 100° C. for a time period of from about 30 minutes to about 6hours to form a pre-catalyst. In an alternative aspect, prior to dryingthe titanated support as disclosed herein the chromium-containingcompound and the titanated support may be contacted to form the additionproduct that may be dried by heating the addition product to atemperature in a range of from about 25° C. to about 300° C.;alternatively, from about 50° C. to about 150° C.; or alternatively,from about 75° C. to about 100° C. The method further comprisesmaintaining the temperature of the addition product in the range of fromabout 25° C. to about 300° C.; alternatively, from about 50° C. to about150° C.; or alternatively, from about 75° C. to about 100° C. for a timeperiod of from about 30 minutes to about 6 hours to form thepre-catalyst. In yet another alternative aspect, the chromium-containingcompound and the silica support may be contacted to form achromium-silica support that may be contacted with the STM to form theaddition product that may be dried by heating the addition product to atemperature in a range of from about 25° C. to about 300° C.;alternatively, from about 50° C. to about 150° C.; or alternatively,from about 75° C. to about 100° C. The method further comprisesmaintaining the temperature of the addition product in the range of fromabout 25° C. to about 300° C.; alternatively, from about 50° C. to about150° C.; or alternatively, from about 75° C. to about 100° C. for a timeperiod of from about 30 minutes to about 6 hours to form thepre-catalyst.

In yet a further aspect, a method for preparation of an olefinpolymerization catalyst comprises contacting a titanium-containingcompound and a nitrogen-containing compound, both of the type disclosedherein, to form a basic mixture. The method may further comprisecontacting a solvent and a carboxylic acid, both of the type disclosedherein, to form an acidic mixture. The basic mixture and the acidicmixture may be contacted to form a solubilized titanium mixture (STM) asdisclosed herein, e.g., the basic mixture may be added to the acidicmixture to form the STM. In some aspects, the basic mixture is added tothe acidic mixture as a single portion of an amount sufficient to forman equivalent molar ratio of titanium-containing compound to carboxylicacid of about 1:2. In a particular aspect, an amount of basic mixture tobe added to the acidic mixture is determined with an acid-baseindicator, (e.g., bromocresol green), wherein the basic mixture is addedto the acidic mixture in multiple portions and wherein a single portioncomprises from about 3% to about 10% of the amount of basic mixture thatcomprises an equivalent molar ratio of titanium-containing compound tocarboxylic acid of about 1:2. Addition of the multiple portions of thebasic mixture may be ceased when a green-hued endpoint of a bromocresolgreen indicator is achieved. In some aspects, the green-hued endpoint ofthe bromocresol green indicator correlates to a pH value within the STMof about 4.0. In a further aspect, addition of the basic mixture to theacidic mixture comprises neutralizing the acidic mixture partially; oralternatively, neutralizing the acidic mixture completely. The methodfor preparation of the olefin polymerization catalyst may furthercomprise contacting a chromium-silica support of the type disclosedherein and the STM to form an addition product. In a further aspect, theaddition product may be dried by heating the addition product to atemperature in a range of from about 25° C. to about 300° C.;alternatively, from about 50° C. to about 150° C.; or alternatively,from about 75° C. to about 100° C. The method further comprisesmaintaining the temperature of the addition product in the range of fromabout 25° C. to about 300° C.; alternatively, from about 50° C. to about150° C.; or alternatively, from about 75° C. to about 100° C. for a timeperiod of from about 30 minutes to about 6 hours to form thepre-catalyst.

In a still further aspect, a method for preparation of an olefinpolymerization catalyst comprises contacting a titanium-containingcompound and a nitrogen-containing compound, both of the type disclosedherein, to form a basic mixture. The method may further comprisecontacting a solvent and a carboxylic acid, both of the type disclosedherein, to form an acidic mixture. The basic mixture and the acidicmixture may be contacted to form a solubilized titanium mixture (STM) asdisclosed herein, e.g., the basic mixture may be added to the acidicmixture to form the STM. In some aspects, the basic mixture is added tothe acidic mixture as a single portion of an amount sufficient to forman equivalent molar ratio of titanium-containing compound to carboxylicacid of about 1:2. In a particular aspect, an amount of basic mixture tobe added to the acidic mixture is determined with an acid-baseindicator, (e.g., bromocresol green), wherein the basic mixture is addedto the acidic mixture in multiple portions and wherein a single portioncomprises from about 3% to about 10% of the amount of basic mixture thatcomprises an equivalent molar ratio of titanium-containing compound tocarboxylic acid of about 1:2. Addition of the multiple portions of thebasic mixture may be ceased when a green-hued endpoint of a bromocresolgreen indicator is achieved. In some aspects, the green-hued endpoint ofthe bromocresol green indicator correlates to a pH value within the STMof about 4.0. In a further aspect, addition of the basic mixture to theacidic mixture comprises neutralizing the acidic mixture partially; oralternatively, neutralizing the acidic mixture completely. The methodfor preparation of the olefin polymerization catalyst may furthercomprise contacting a silica support of the type disclosed herein andthe STM to form a titanated support. In a further aspect, the titanatedsupport may be dried by heating the titanated support to a temperaturein a range of from about 25° C. to about 300° C.; alternatively, fromabout 50° C. to about 150° C.; or alternatively, from about 75° C. toabout 100° C. The method further comprises maintaining the temperatureof the titanated support in the range of from about 25° C. to about 300°C.; alternatively, from about 50° C. to about 150° C.; or alternatively,from about 75° C. to about 100° C. for a time period of from about 30minutes to about 6 hours to form a dried titanated support. The methodmay further comprise contacting a chromium-containing compound of thetype disclosed herein and the dried titanated support to form anaddition product that may be dried by heating the addition product to atemperature in a range of from about 25° C. to about 300° C.;alternatively, from about 50° C. to about 150° C.; or alternatively,from about 75° C. to about 100° C. The method further comprisesmaintaining the temperature of the addition product in the range of fromabout 25° C. to about 300° C.; alternatively, from about 50° C. to about150° C.; or alternatively, from about 75° C. to about 100° C. for a timeperiod of from about 30 minutes to about 6 hours to form a pre-catalyst.In an alternative aspect, prior to drying the titanated support asdisclosed herein the chromium-containing compound and the titanatedsupport may be contacted to form the addition product that may be driedby heating the addition product to a temperature in a range of fromabout 25° C. to about 300° C.; alternatively, from about 50° C. to about150° C.; or alternatively, from about 75° C. to about 100° C. The methodfurther comprises maintaining the temperature of the addition product inthe range of from about 25° C. to about 300° C.; alternatively, fromabout 50° C. to about 150° C.; or alternatively, from about 75° C. toabout 100° C. for a time period of from about 30 minutes to about 6hours to form the pre-catalyst. In yet another alternative aspect, thechromium-containing compound and the silica support may be contacted toform a chromium-silica support that may be contacted with the STM toform the addition product that may be dried by heating the additionproduct to a temperature in a range of from about 25° C. to about 300°C.; alternatively, from about 50° C. to about 150° C.; or alternatively,from about 75° C. to about 100° C. The method further comprisesmaintaining the temperature of the addition product in the range of fromabout 25° C. to about 300° C.; alternatively, from about 50° C. to about150° C.; or alternatively, from about 75° C. to about 100° C. for a timeperiod of from about 30 minutes to about 6 hours to form thepre-catalyst.

Utilization of a solubilized titanium mixture (STM) in the preparationof an olefin polymerization catalyst of the present disclosure may beadvantageous because the STM can facilitate the association of titaniumwith a silica support in the presence of an aqueous solvent (e.g.,water). Further advantages may occur when the STM utilized to form theolefin polymerization catalyst comprises an aqueous solvent (e.g.,water). The solubility of titanium in the aqueous solvent may besufficient to allow the use of spray drying methodologies for contactingthe STM and the silica support. Spray drying as used herein refers to amethod of producing a dry powder from a liquid or slurry by rapidlydrying with a hot gas. Spray drying methodologies may be utilized in thepreparation of olefin polymerization catalysts in a continuousproduction method with the potential to produce large volumes of olefinpolymerization catalysts. Spray drying methodologies may also beutilized in the preparation of olefin polymerization catalysts having aconsistent particle size distribution. Utilization of the STM comprisingthe aqueous solvent may permit use of a hydrated silica support andobviate the thermal treatment required for anhydrous methods of catalystpreparation, (e.g., drying the hydrated silica support prior to contactwith any other catalyst component).

In some aspects of the present disclosure, contacting of the componentsutilized in preparation of the olefin polymerization catalyst may becarried out in the presence of a reaction media. In a further aspect,the reaction media may be formed during contacting of the componentsutilized in preparation of the olefin polymerization catalyst. Thereaction media may comprise a solvent (e.g., water) as disclosed hereinand one or more liquids associated with the components utilized inpreparation of the olefin polymerization catalyst (e.g., waterassociated with the silica support). In an aspect, the reaction mediaexcludes any solid component utilized in the preparation of the olefinpolymerization catalyst disclosed herein (e.g., silica support and anysolids associated therewith). In some aspects, a sum of an amount ofwater present in the reaction media may be in a range of from about 1wt. % to about 99 wt. %; alternatively, from about 1 wt. % to about 50wt. %; alternatively, from about 1 wt. % to about 20 wt. %; oralternatively, from about 1 wt. % to about 10 wt. % based upon the totalweight of the reaction media. In yet a further aspect, the reactionmedia may contain greater than about 20 wt. % water; alternatively,about 40 wt. % water; alternatively, about 60 wt. % water;alternatively, about 80 wt. % water; or alternatively, about 90 wt. %water based upon the total weight of the reaction media wherein thewater may originate from one or more components utilized in preparationof the olefin polymerization catalyst.

In any aspect of the present disclosure, a method for preparation of anolefin polymerization catalyst further comprises activating apre-catalyst prepared as disclosed herein via a calcination step. Insome aspects, calcination of the pre-catalyst comprises heating thepre-catalyst in an oxidizing environment to produce the olefinpolymerization catalyst. For example, the pre-catalyst may be calcinedby heating the pre-catalyst in the presence of air to a temperature in arange of from about 400° C. to about 1000° C.; alternatively, from about500° C. to about 900° C.; or alternatively, from about 500° C. to about850° C. Calcination of the pre-catalyst may further comprise maintainingthe temperature of the pre-catalyst in the presence of air in the rangeof from about 400° C. to about 1000° C.; alternatively, from about 500°C. to about 900° C.; or alternatively, from about 500° C. to about 850°C. for a time period in a range of from about 1 minute to about 24hours; alternatively, from about 1 minute to about 12 hours;alternatively, from about 20 minutes to about 12 hours; alternatively,from about 1 hour to about 10 hours; alternatively, from about 3 hoursto about 10 hours; or alternatively, from about 3 hours to about 5 hoursto produce the olefin polymerization catalyst.

The olefin polymerization catalysts of the present disclosure aresuitable for use in any olefin polymerization method, using varioustypes of polymerization reactors. In an aspect of the presentdisclosure, a polymer of the present disclosure is produced by anyolefin polymerization method, using various types of polymerizationreactors. As used herein, “polymerization reactor” includes any reactorcapable of polymerizing olefin monomers to produce homopolymers and/orcopolymers. Homopolymers and/or copolymers produced in the reactor maybe referred to as resin and/or polymers. The various types of reactorsinclude, but are not limited to those that may be referred to as batch,slurry, gas-phase, solution, high pressure, tubular, autoclave, or otherreactor and/or reactors. Gas phase reactors may comprise fluidized bedreactors or staged horizontal reactors. Slurry reactors may comprisevertical and/or horizontal loops. High pressure reactors may compriseautoclave and/or tubular reactors. Reactor types may include batchand/or continuous processes. Continuous processes may use intermittentand/or continuous product discharge or transfer. Processes may alsoinclude partial or full direct recycle of un-reacted monomer, un-reactedcomonomer, olefin polymerization catalyst and/or co-catalysts, diluents,and/or other materials of the polymerization process.

Polymerization reactor systems of the present disclosure may compriseone type of reactor in a system or multiple reactors of the same ordifferent type, operated in any suitable configuration. Production ofpolymers in multiple reactors may include several stages in at least twoseparate polymerization reactors interconnected by a transfer systemmaking it possible to transfer the polymers resulting from the firstpolymerization reactor into the second reactor. Alternatively,polymerization in multiple reactors may include the transfer, eithermanual or automatic, of polymer from one reactor to subsequent reactoror reactors for additional polymerization. Alternatively, multi-stage ormulti-step polymerization may take place in a single reactor, whereinthe conditions are changed such that a different polymerization reactiontakes place.

The desired polymerization conditions in one of the reactors may be thesame as or different from the operating conditions of any other reactorsinvolved in the overall process of producing the polymer of the presentdisclosure. Multiple reactor systems may include any combinationincluding, but not limited to, multiple loop reactors, multiple gasphase reactors, a combination of loop and gas phase reactors, multiplehigh pressure reactors, and a combination of high pressure with loopand/or gas reactors. The multiple reactors may be operated in series orin parallel. In an aspect of the present disclosure, any arrangementand/or any combination of reactors may be employed to produce thepolymer of the present disclosure.

According to one aspect of the present disclosure, the polymerizationreactor system may comprise at least one loop slurry reactor. Suchreactors are commonplace, and may comprise vertical or horizontal loops.Generally, continuous processes may comprise the continuous introductionof a monomer, an olefin polymerization catalyst, and/or a diluent into apolymerization reactor and the continuous removal from this reactor of asuspension comprising polymer particles and the diluent. Monomer,diluent, olefin polymerization catalyst, and optionally any comonomermay be continuously fed to a loop slurry reactor, where polymerizationoccurs. Reactor effluent may be flashed to remove the liquids thatcomprise the diluent from the solid polymer, monomer and/or comonomer.Various technologies may be used for this separation step, including butnot limited to, flashing that may include any combination of heataddition and pressure reduction; separation by cyclonic action in eithera cyclone or hydrocyclone; separation by centrifugation; or otherappropriate method of separation.

Typical slurry polymerization processes (also known as particle-formprocesses) are disclosed in U.S. Pat. Nos. 3,248,179, 4,501,885,5,565,175, 5,575,979, 6,239,235, 6,262,191 and 6,833,415, for example;each of which are herein incorporated by reference in their entirety.

Diluents suitable for use in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used. An example is the polymerization ofpropylene monomer as disclosed in U.S. Pat. No. 5,455,314, which isincorporated by reference herein in its entirety.

According to yet another aspect of the present disclosure, thepolymerization reactor may comprise at least one gas phase reactor. Suchsystems may employ a continuous recycle stream containing one or moremonomers continuously cycled through a fluidized bed in the presence ofthe olefin polymerization catalyst under polymerization conditions. Arecycle stream may be withdrawn from the fluidized bed and recycled backinto the reactor. Simultaneously, polymer product may be withdrawn fromthe reactor and new or fresh monomer may be added to replace thepolymerized monomer. Such gas phase reactors may comprise a process formulti-step gas-phase polymerization of olefins, in which olefins arepolymerized in the gaseous phase in at least two independent gas-phasepolymerization zones while feeding an olefin polymerizationcatalyst-containing polymer formed in a first polymerization zone to asecond polymerization zone. One type of gas phase reactor suitable foruse is disclosed in U.S. Pat. Nos. 4,588,790, 5,352,749, and 5,436,304,each of which is incorporated by reference in its entirety herein.

According to still another aspect of the present disclosure, ahigh-pressure polymerization reactor may comprise a tubular reactor oran autoclave reactor. Tubular reactors may have several zones wherefresh monomer, initiators, or olefin polymerization catalysts are added.Monomer may be entrained in an inert gaseous stream and introduced atone zone of the reactor. Initiators, olefin polymerization catalysts,and/or catalyst components may be entrained in a gaseous stream andintroduced at another zone of the reactor. The gas streams may beintermixed for polymerization. Heat and pressure may be employedappropriately to obtain optimal polymerization reaction conditions.

According to yet another aspect of the present disclosure, thepolymerization reactor may comprise a solution polymerization reactorwherein the monomer is contacted with the olefin polymerization catalystcomposition by suitable stirring or other means. A carrier comprising anorganic diluent or excess monomer may be employed. If desired, themonomer may be brought in the vapor phase and into contact with thecatalytic reaction product, in the presence or absence of liquidmaterial. The polymerization zone is maintained at temperatures andpressures that will result in the formation of a solution of the polymerin a reaction medium. Agitation may be employed to obtain bettertemperature control and to maintain uniform polymerization mixturesthroughout the polymerization zone. Adequate means are utilized fordissipating the exothermic heat of polymerization.

Polymerization reactors suitable for use in the present disclosure mayfurther comprise any combination of at least one raw material feedsystem, at least one feed system for an olefin polymerization catalystor catalyst components, and/or at least one polymer recovery system.Suitable reactor systems for the present disclosure may further comprisesystems for feedstock purification, catalyst storage and preparation,extrusion, reactor cooling, polymer recovery, fractionation, recycle,storage, loadout, laboratory analysis, and process control.

Conditions that are controlled for polymerization efficiency and toprovide polymer properties include, but are not limited to, temperature,pressure, type and quantity of the olefin polymerization catalyst orco-catalyst, and the concentrations of various reactants. Polymerizationtemperature can affect catalyst productivity, polymer molecular weightand molecular weight distribution. Suitable polymerization temperaturesmay be any temperature below the de-polymerization temperature,according to the Gibbs Free Energy Equation. Typically, this includesfrom about 60° C. to about 280° C., for example, and/or from about 70°C. to about 110° C., depending upon the type of polymerization reactorand/or polymerization process.

Suitable pressures will also vary according to the reactor andpolymerization process. The pressure for liquid phase polymerization ina loop reactor is typically less than 1000 psig (6.9 MPa). Pressure forgas phase polymerization is usually in a range of from about 200 psig(1.4 MPa)-500 psig (3.45 MPa). High-pressure polymerization in tubularor autoclave reactors is generally run in a range of from about 20,000psig (138 MPa) to 75,000 psig (518 MPa). Polymerization reactors canalso be operated in a supercritical region occurring at generally highertemperatures and pressures. Operation at conditions above the criticalpoint as indicated by a pressure/temperature diagram (supercriticalphase) may offer advantages.

The concentration of various reactants can be controlled to producepolymers with certain physical and mechanical properties. The proposedend-use product that will be formed by the polymer and the method offorming that product may be varied to determine the desired finalproduct properties. Mechanical properties include, but are not limitedto tensile strength, flexural modulus, impact resistance, creep, stressrelaxation and hardness test values. Physical properties include, butare not limited to density, molecular weight, molecular weightdistribution, melting temperature, glass transition temperature,temperature melt of crystallization, density, stereoregularity, crackgrowth, short chain branching, long chain branching and rheologicalmeasurements.

The concentrations of monomer, comonomer, hydrogen, co-catalyst,modifiers, and electron donors are generally important in producingspecific polymer properties. Comonomer may be used to control productdensity. Hydrogen may be used to control product molecular weight.Co-catalysts may be used to alkylate, scavenge poisons and/or controlmolecular weight. The concentration of poisons may be minimized, aspoisons may impact the reactions and/or otherwise affect polymer productproperties. Modifiers may be used to control product properties andelectron donors may affect stereoregularity.

Polymers such as polyethylene homopolymers and copolymers of ethylenewith other mono-olefins may be produced in the manner described aboveusing the olefin polymerization catalysts prepared as described herein.Polymers produced as disclosed herein may be formed into articles ofmanufacture or end use articles using techniques known in the art suchas extrusion, blow molding, injection molding, fiber spinning,thermoforming, and casting. For example, a polymer resin may be extrudedinto a sheet, which is then thermoformed into an end use article such asa container, a cup, a tray, a pallet, a toy, or a component of anotherproduct. Examples of other end use articles into which the polymerresins may be formed include pipes, films, and bottles.

A method of the present disclosure comprises contacting an olefinpolymerization catalyst of the type described with an olefin monomerunder conditions suitable for the formation of a polyolefin andrecovering the polyolefin. In an aspect the olefin monomer is anethylene monomer and the polyolefin is an ethylene polymer(polyethylene).

Polyethylene prepared as described herein may be characterized by a highload melt index (HLMI), in a range of from about 1 g/10 min. to about1000 g/10 min.; alternatively, from about 3 g/10 min. to about 300 g/10min.; alternatively, from about 6 g/10 min. to about 100 g/10 min.; oralternatively, from about 15 g/10 min. to about 40 g/10 min. In afurther aspect, the polyethylene prepared as described herein may becharacterized by an HLMI that is from about 1.5 to about 15 timesgreater than the HLMI of a polymer produced by utilizing an otherwisesimilar olefin polymerization catalyst produced in the absence of anitrogen-containing compound.

In a particular aspect, polyethylene may be prepared with a de-titanatedcatalyst that was produced from a water-extracted pre-catalyst. In afurther aspect, the water-extracted pre-catalyst is a pre-catalyst thatwas extracted with water prior to being calcined. For example, apre-catalyst prepared as described herein may be extracted with waterand subsequently calcined to provide the de-titanated catalyst (i.e.,olefin polymerization catalyst derived from the water-extractedpre-catalyst). In a further aspect, polyethylene prepared with ade-titanated catalyst may be characterized by an HLMI in the range offrom about 1 dg/min to about 7 dg/min. Such an HMLI value can indicatethat the de-titanated catalyst has an amount of titanium based upon anamount of silica in a range of from about 0 wt. % to about 1 wt. %; oralternatively, about 0.1 wt. % to about 0.5 wt. %.

The melt index (MI) represents the rate of flow of a molten polymerthrough an orifice of 0.0825 inch diameter when subjected to a force of2,160 grams at 190° C. as determined in accordance with ASTM D1238-82condition E. The 110 represents the rate of flow of a molten polymerthrough an orifice of 0.0825 inch diameter when subjected to a force of10,000 grams at 190° C. as determined in accordance with ASTM D1238-82condition N. The HLMI (high load melt index) represents the rate of flowof a molten polymer through an orifice of 0.0825 inch diameter whensubjected to a force of 21,600 grams at 190° C. as determined inaccordance with ASTM D1238-82 condition F.

EXAMPLES

The following examples are given as particular aspects of the presentdisclosure and to demonstrate the practice and advantages thereof. It isunderstood that the examples are given by way of illustration and arenot intended to limit the specification or the claims to follow in anymanner.

It will be appreciated by one skilled in the art that the surfaces ofoxides, including silica (SiO₂) and titania (TiO₂), commonly terminatewith hydroxyl groups which are protic groups that can participate inacid-base reactions. In strongly acidic conditions the hydroxyl groupscan be protonated to establish a positive charge upon the oxide surface.In strongly alkaline conditions the hydroxyl groups may be deprotonatedto establish a negative charge upon the oxide surface. There is a pHvalue somewhere between the two limits at which zero net charge existsupon the oxide surface. The pH value correlating to zero net charge isthe isoelectric point. Every oxide possesses a characteristic acidityand a specific isoelectric point controlled by the chemical propertiesof the metal or non-metal element of the oxide.

The FIGURE displays zeta potential as a function of solution pH valuefor silica and titania along with the isoelectric point value of bothoxides. A curve of the coulombic Si—Ti attraction is also shown. Zetapotential is the difference in electrical charge potential existingbetween the surface of a solid particle immersed in a conducting liquid(e.g., water) and the bulk of the liquid. The FIGURE displays thattitania is positively charged and silica is negatively charged within azone of pH values between 3.0 and 5.0. The FIGURE also indicates thatcoulombic Si—Ti attraction is greatest around a pH value of about 4.0.Not wishing to be limited by theory, highly effective titanation of anolefin polymerization catalyst from an aqueous Ti solution may resultwhen the coulombic Si—Ti attraction is maximized by maintaining a pHvalue of the solution at about 4.0. To explore this theory, severalseries of experiments were conducted to establish conditions leading tothe formation of an aqueous Ti solution with a pH value of about 4.0.

All of the silica support materials, chemical reagents, and solventsdescribed herein were used as received and were not dried prior to use.

Catalysts used in the experiments described below include Magnapore® acommercial Cr/silica-titania catalyst obtained from W. R. Grace andCompany, and activated at various temperatures. Magnapore® is made bytergellation of Si, Ti and Cr, containing 2.5 wt. % Ti and 1 wt. % Cr,having a surface of about 500 m²/g, a pore volume of 2.5 mL/g, and anaverage particle size of about 130 microns. Another commercialCr/silica-titania catalyst that was used, called C-25305HM, was obtainedfrom Philadelphia Quartz (PQ) Corporation. It also contains 2.5 wt. % Tiand 1 wt. % Cr, having has a surface of about 500 m²/g, a pore volume of2.7 mL/g, and an average particle size of about 100 microns. The mainbase catalyst used for the titanations described below was Sylopol®HA30W, a commercial Cr/silica obtained from W. R. Grace. This catalystcontained no titanium but did contain 1 wt. % Cr. It had a surface areaof about 500 m²/g, a pore volume of about 1.6 mL/g, and an averageparticle size of about 100 microns. Three other commercial Cr/silicacatalysts were also used; one called EP30X from PQ Corporation, anotherunder the trade name D-70-150A(LV) from Asahi Glass Corporation (AGC),and the third was Sylopol® 969MPI from W. R. Grace. All three of thesecatalysts contained no titanium but did contain 1 wt. % Cr. All threehad a pore volume of about 1.6 mL/g. EP30X and 969MPI had a surface areaof about 300 m²/g and an average particle size of about 100 microns. AGCD-70-150A(LV) had a surface area of about 400 m²/g and an averageparticle size of about 80 microns.

Activity tests were conducted in a 2.2 liter steel reactor equipped witha marine stirrer running at 400 rpm. The reactor was surrounded by asteel jacket circulating water, the temperature of which was controlledby use of steam and water heat exchangers. These were connected in anelectronic feed-back loop so that the reactor temperature could bemaintained at +/−0.5° C. during the reaction.

Unless otherwise stated, a small amount (0.01 to 0.10 grams normally) ofthe solid chromium catalyst was first charged under nitrogen to the dryreactor. Next about 0.25 g of sulfate-treated alumina (600° C.) wasadded as a scavenger for poisons. Then 1.2 liter of isobutane liquid wascharged and the reactor heated up to the specified temperature, usually105 degrees C. Finally ethylene was added to the reactor to equal afixed pressure, normally 550 psig (3.8 MPa), which was maintained duringthe experiment. The stirring was allowed to continue for the specifiedtime, usually around one hour, and the activity was noted by recordingthe flow of ethylene into the reactor to maintain the set pressure.

After the allotted time, the ethylene flow was stopped and the reactorslowly depressurized and opened to recover a granular polymer powder. Inall cases the reactor was clean with no indication of any wall scale,coating or other forms of fouling. The polymer powder was then removedand weighed. Activity was specified as grams of polymer produced pergram of solid catalyst charged per hour.

Example 1

Several control runs were conducted and the results of the control runsare listed in Table 1. Performance of the experimental catalysts shownin the further examples in terms of productivity, activity, and meltindex potential may be compared to these control runs. Runs 1.10-1.13display the performance of two non-titanated catalysts the latter ofwhich, HA30W, provides a metric of the effectiveness of the titanationsof Runs 1.16-1.18. The titanations displayed in Runs 1.16-1.18 usedTi(OiPr)₄ to titanate HA30W. The titanation in Run 1.15 exposed thesupport to TiCl₄ vapor at 250° C. in an attempt to produce a titanatedcatalyst uncontaminated by organic or alcohol by-products. In both ofthese methods, the support must be dried to remove free water from thesurface, usually by a thermal treatment from about 150° C. to about 800°C. Otherwise the titanium will react with the free adsorbed water and beineffective. In Runs 1.15-1.18 the catalyst was dried at 200° C. beforebeing titanated by either gas phase or anhydrous solvent (usuallyheptane).

TABLE 1 Performance of Reference Catalysts Run Ti Act. Ind. Time Prod.Activity MI |10 HLMI No. Catalyst Base Treatment wt % Temp. min g/gg/g-h dg/min dg/min dg/min 1.1 Magnapore ® none 2.5 871° C. 8 5362 71492.27 29.2 121 1.2 Magnapore ® none 2.5 871° C. 8 1921 4117 1.58 22.7 1081.3 Magnapore ® none 2.5 871° C. 7 2822 3938 0.73 13.7 66.2 1.4Magnapore ® none 2.5 650° C. 6 2071 2825 0.45 30.0 1.5 Magnapore ® none2.5 650° C. 6 1653 3672 0.58 36.3 1.6 Magnapore ® none 2.5 650° C. 73411 5831 0.50 29.7 1.7 Magnapore ® none 2.5 650° C. 7 2150 2283 0.4726.9 1.8 PQ C-25305HM none 2.5 650° C. 5 1535 1674 0.91 52.7 1.9 PQC-25305HM none 2.5 650° C. 5 1596 4352 0.86 53.9 1.10 969MPI none 0 780°C. 20 2830 2326 1.5 8.7 1.11 969MPI none 0 650° C. 18 1835 1835 0.1612.8 1.12 HA30W none 0 650° C. 11 2973 2973 0.87 5.5 1.13 ″ ″ ″ 650° C.18 3117 2309 0.24 4.22 19.6 1.14 D-70-150A(LV) PPC C1 Act. 3.0 650° C.12 3221 2577 0.35 6.3 30.5 1.15 D-70-150A(LV) TiCl₄ vapor 3.0 650° C. 63092 2728 0.46 8.20 36.3 1.16 HA30W Ti(OiPr)₄/C7 3.5 650° C. 8 2534 27150.40 7.70 36.7 1.17 HA30W Ti(OiPr)₄/C7 4.8 650° C. 11 2455 1259 0.234.69 21.5 1.18 ″ ″ ″ ″ 5 2271 2349 0.29 5.91 28.0 Run at 105° C., 550psig

Example 2: Acidic Titanation

The first series of experiments studied the ability of carboxylic acidsto form an acidic Ti-containing solution capable of providing effectivetitanation to an olefin polymerization catalyst of the type disclosedherein (i.e., catalyst). The results are listed in Table 2. All of theseexperiments started with hydrated silica supports that were notsubjected to thermal treatment prior to contact with any other catalystcomponent. The carboxylic acids listed were mixed with water, or analternate solvent system as listed, to form a solution, but in all casesthe solvents were not dried and no attempt was made to use anhydrousconditions. Ti(OiPr)₄ was added and when dissolution occurred the acidicTi-containing solution formed thereby was impregnated onto achromium-silica support (HA30W). The product was then dried and calcinedin air for three hours at 650° C. prior to use in polymerizationexperiments.

Table 2 summarizes the study of a variety of carboxylic acids. The useof carboxylic acids alone (no base added) did not produce very effectivetitanation. Run 2.2, which used acetic acid in propanol solvent,provided the most effective titanation. Successful results were alsoobserved when HA30W was impregnated with the acidic Ti-containingsolution and dropped into a 300° C. activator tube (“hot-drop”, Runs2.12-2.16). This rapid method of drying was moderately effective asevidenced by the higher melt index obtained when the catalyst wasproduced using this method compared to oven drying. The “hot-drop”method of drying resulted in more effective titanation when citric acidwas used in place of oxalic acid. This result may have occurred becausethe first pK_(a) of citric acid (3.13) is higher than the first pK_(a)of oxalic acid (1.23). The lower acidity of citric acid may produce aTi-containing solution with a pH value that is higher and closer to 4.0when compared to the Ti-containing solution produced with oxalic acid.

TABLE 2 Titanation with Simple Acids Ind. Time Prod. Activity MI |10HLMI Run No. Acid/Solvent Acid/Ti min g/g g/g-h dg/min dg/min dg/min 2.1Acetic Acid Solvent Large XS 7 1453 1478 0.09 2.39 11.0 2.2 AceticAcid/n-propanol Large XS 5 3178 3467 0.49 8.69 39.1 2.3 Glycolic acid4:1 17 3098 3320 0.97 5.7 2.4 Glycolic acid 2:1 9 2186 2851 0.37 2.9 2.5HNO₃ 1.7% 15 2846 2339 0.08 1.1 2.6 HNO₃/H₂O + n-propanol 1.7% 16 31113010 0.002 0.15 1.8 2.7 Phosphonoacetic acid 4:1 7 867 627 1.14 6.0 2.8Oxalic acid, hot-drop** 3:1 13 2933 3088 1.03 6.4 2.9 ″ ″ 9 2848 32241.59 9.0 2.10 Citric acid, hot-drop** 3:1 9 3737 3114 0.11 3.41 17.32.11 ″ ″ 14 2986 5599 0 1.53 9.0 2.12 ″ ″ 9 3238 1833 0 3.02 16.0Catalysts used virgin HA30W base, contained 3.5 wt % Ti, used water assolvent, were activated at 650° C. Runs were normally conducted at 105°C., 550 psig. * Run occurred at 100° C. with 5 mL 1-hexene, 550 psig**These catalysts were dried by being dropped into a hot activator tubeset at 300° C.

Example 3: Alkaline Titanation

The next series of experiments studied the ability of a base to form analkaline Ti-containing solution capable of providing effectivetitanation to a catalyst. The results are listed in Table 3. Theexperimental approach was essentially identical to the method describedin Example 2. Ti dissolved in some strong bases, e.g., organic baseswere effective, but ammonium hydroxide and alkali hydroxides were noteffective. Quaternary ammonium hydroxides dissolved Ti but unchargedprimary, secondary, or tertiary amines were less effective. The meltindex potentials resulting from the use of alkaline solutions were alllow, like the non-titanated support, and thus did not display evidenceof effective titanation of the chromium-silica support.

TABLE 3 Titanation with Simple Bases Ind. Time Prod Activity MI |10 HLMIRun No. Base/Solvent Base/Ti min g/g g/g-h dg/min dg/min dg/min 3.1NEt₄OH 4:1 34 0 0 3.2 ″ 4:1  0 0 0 3.3 NEt₄OH 1:1 24 2314 1876 0 0.282.6 3.4 NTA + NEt₄OH 1.2:2:1   Not soluble 3.5 AcAc + NEt₄OH 1:1:1 182474 2699 0.20 2.6 3.6 Dimethylglycine 4.5:1 NA 2749 NA 0.018 1.3 7.03.7 ″ 16 3060 3165 0.013 1.0 5.9 3.8 Triethanolamine 2:1 Not soluble 3.9Dimethylaminoethanol 1:1 19 1186 1581 2.6 3.10 NMe₄OH + Et-diamine 2:2:1 0 67 59 3.11 NMe₄OH + Et-diamine 0.6:4:1   37 3035.97 1023 0 0.0 1.63.12 Ethylenediamine 4:1 Not soluble 3.13 Arginine 4:1 Not solubleCatalysts used virgin HA30W base, contained 3.5 wt % Ti, and wereactivated at 650° C. Runs were normally conducted at 105° C. and 550psig. * Run at 100° C. with 5 mL 1-hexene, 550 psig NTA =nitrilotetraacetic acid

Example 4: pH Adjustment with Ammonium Hydroxides

The results in Table 2 and Table 3 confirmed that attaching titania tosilica can be problematic at both high pH and low pH. The next series ofexperiments were conducted to probe the theory that maximum coulombicSi—Ti attraction occurs at a pH value of about 4.0. Ti(OiPr)₄ washydrolyzed to titania which was dissolved in an aqueous solution ofoxalic acid (2 equivalents of oxalic acid per Ti), to produce an acidicTi-containing solution with a pH value of about 1. Ammonium hydroxide,or a quaternary derivative as listed in Table 4, was added until agreen-hued endpoint of a bromocresol green indicator was reached,indicating a pH value of about 4.0, to produce a solubilized Ti mixture(STM) of the type disclosed herein. The stoichiometry required topartially neutralize the acidic Ti-containing solution, and produce theSTM thereby, was usually about two equivalents of base per Ti. An HA30Wsupport was impregnated with the STM and the product was dried andcalcined in air for three hours at 650° C. prior to use inpolymerization experiments.

The results listed in Table 4 indicate that the approach was successful.Quaternary ammonium hydroxides were more effective when compared toammonium hydroxide. This result may be explained by the lower volatilityof tetraalkylammonium hydroxides. The results in Table 4 also indicatethat the amount of base used to prepare the STM impacted the melt indexpotential conferred by the resultant catalyst. The method also allowedfor effective titanation upon a hydrogel, rather than a pre-formedsilica support (Run 4.16). The catalyst of Run 4.6 was prepared byinverse addition and displayed remarkable performance: Ti was dissolvedin aqueous NMe₄OH to form an alkaline solution that was added to anaqueous solution of oxalic acid to prepare the STM used for impregnationof the HA30W support.

TABLE 4 Partial Neutralization with Ammonium Hydroxides Ind. Time Prod.Activity MI |10 HLMI Run No. Base Base/Ti min g/g g/g-h dg/min dg/mindg/min 4.1 NH₄OH 2.0 11 2570 3281 0.10 3.16 16.8 4.2 NH₄OH 2.4 13 31443092 0.12 3.26 16.8 4.3 NH₄OH 2.7 11 2978 2414 0.14 3.62 17.6 4.4 NMe₄OH2.0 12 3181 3976 0.51 9.1 44.4 4.5 NMe₄OH 2.1 11 3402 3581 0.32 6.4 31.84.6 NMe₄OH 2.0 R 13 1508 542 1.63 28.8 143 4.7 NMe₄OH 1R 1OAPrecipitation occurred 4.8 NEt₄OH 1.0 18 2943 4772 0.14 3.39 16.9 4.9NEt₄OH 1.5 16 3062 5104 0.20 4.22 21.0 4.10 NEt₄OH ″ 11 2182 3193 0.133.45 18.0 4.11 NEt₄OH 1.5 13 2415 3916 0.24 5.32 26.8 4.12 NEt₄OH 2.0 133165 6126 0.27 5.34 26.8 4.13 NEt₄OH 2.5 12 3226 6244 0.18 3.95 21.24.14 NEt₄OH 3.0 22 2865 2605 0.00 1.20 6.8 4.15 NEt₄OH 4.0 Precipitationoccured 4.16 NEt₄OH 2.0 H 18 2769 1678 0.25 5.48 27.8 4.17 NEt₄OH 2.0 wCr 9 3157 2282 0.28 5.70 28.4 Ti(OiPr)₄ was dissolved in 2 eq. of oxalicacid solution, then base was added to partially neutralize the acid. Thesolution was then added to virgin HA30W and dried. Each catalystcontained 3.5 wt % Ti and was activated at 650° C. Runs were conductedat 105° C., 550 psig. R: Ti was dissolved in base, then the acid wasadded. H: A hydrogel was used in place of a pre-formed silica support.Cr: Cr was added to the oxalic acid, rather than being on the catalystinitially.

Example 5: pH Adjustment with Urea

The next series of experiments studied the ability of urea to partiallyneutralize an acidic Ti-containing solution and create an STM capable ofproviding effective titanation to a catalyst. Urea is easily decomposedupon heating into volatile products. Replacement of carbon-containingcatalyst components with urea compounds has the potential to reduceemissions of volatile organic and highly reactive volatile organiccompounds created during calcination of the catalysts. The experimentalapproach was essentially identical to the method described in Example 4but without the use of the bromocresol green indicator. The results areshown in Table 5. Addition of urea to the acidic Ti-containing solutionprovided increasingly effective titanation as the amount of urea wasincreased. This effect was not observed in experiments that investigatedthe use of urea in spray drying applications, possibly because the ureadecomposed and/or evaporated during the spray drying operation.Effective titanation was also observed with N,N′-dimethyl urea, which isless volatile than urea.

TABLE 5 Oxalic Acid with Urea Ind. Time Prod. Activity MI |10 HLMI RunNo. Base Urea/Ti min g/g g/g-h dg/min dg/min dg/min 5.1 Urea 1:1 15 38044389 0.11 3.04 15.3 5.2 Urea 2:1 11 4519 3819 0.49 6.00 27.8 5.3 Urea3:1 10 2553 4140 0.26 5.86 29.4 5.4 Urea 3:1 8 2370 3231 0.28 6.14 30.05.5 Urea 4:1 16 3423 4668 0.44 8.07 40.0 5.6 N,N′-Dimethyl urea 2:1 143712 5179 0.36 6.87 34.3 Ti(OiPr)₄ was dissolved in 2 eq of oxalic acidsolution, then base was added to partially neutralize the acid. Thesolution was then added to virgin HA30W and dried. Each catalystcontained 3.5 wt % Ti and was activated at 650° C. Runs were conductedat 105° C., 550 psig.

Example 6: pH Adjustment with Alkanolamines

The next series of experiments studied the ability of alkanolamines topartially neutralize an acidic Ti-containing solution and create an STMcapable of providing effective titanation to a catalyst. Ethanol aminesand isopropanol amines were chosen because they generally exhibit lowtoxicity, have low cost, are readily available from multiple sources,and have less odor in contrast to most amines. The experimental approachwas essentially identical to the method described in Example 5 and theresults are shown in Table 6. The results were varied and bulkier aminesappeared to perform best. Not wishing to be limited by theory, thiscould be a result of the lower volatility of the bulkier compoundsand/or the lower permittivity of Ti ions resulting from the bulkiercompounds. Dimethylaminoethanol (DMAE) provided a relatively high meltindex, is low in cost, available from multiple suppliers, and has lowodor. The catalyst of Run 6.11 was prepared by dissolving titania intotwo equivalents of aqueous oxalic acid, followed by addition of twoequivalents of DMAE to form a solubilized Ti solution (STM) of the typedisclosed herein. An HA30W support was impregnated with the STM to forma titanated support that was dried in vacuum conditions overnight at100° C. The resultant dried titanated support was extracted with waterprior to being calcined at 650° C. and subjected to polymerizationexperiments. The melt index data suggest that the catalyst hadexperienced extensive loss of Ti, presumably during the water extractionstep. This observation indicates that the Ti may not have been attachedthoroughly to the silica after drying at 100° C. and supports previousobservations that attachment between Ti and silica occurs at leastpartly at temperatures greater than 150° C.

TABLE 6 Oxalic Acid with Alkanol Amines Ind. Time Prod. Activity MI |10HLMI Run No. Catalyst Base OA/Ti Base Base/Ti min g/g g/g-h dg/mindg/min dg/min 6.1 HA30W 2.0 Ethanolamine 2.0 10 3627 5062 0.29 5.9 30.76.2 HA30W 2.0 Ethanolamine 2.0 12 3621 3394 0.46 8.4 40.4 6.3 HA30W 1.5Ethanolamine  1.35 10 3157 3105 0.21 4.6 22.7 6.4 HA30W 2.0Diethanolamine 2.0 10 2977 3370 0.42 7.9 39.9 6.5 HA30W 2.0Triethanolamine 2.0 12 3142 3928 0.30 6.2 31.0 6.6 HA30W 2.0 DMAE 2.0 134179 4179 0.64 10.7 52.1 6.7 HA30W 2.0 DMAE 2.0 13 3329 3504 0.45 8.441.2 6.8 HA30W 3.0 DMAE 3.0 8 3403 3646 0.33 6.8 34.1 6.9 HA30W 2.0 DMAE3.0 8 3170 2291 0.26 5.7 28.9 6.10 HA30W 2.0 DMAE 3.0 6 2984 3197 0.194.9 25.6 6.11 HA30W 2.0 DMAE * 2.0 15 2467 1495 0.09 1.3 7.0 6.12 969MS2.0 DMAE † 2.0 10 3510 4213 0.73 13.2 66.2 6.13 969MS 2.0 DMAE ‡ 2.0 93192 3547 1.12 18.1 84.1 6.14 Evonik 2.0 DMAE 2.0 10 2784 6425 0.66 12.461.1 6.15 Evonik 2.0 DMAE 2.0 14 2784 3212 0.97 16.4 79.6 6.16 HA30W 2.0Diglycolamine 2.0 12 3015 3769 0.54 9.6 47.3 6.17 HA30W 2.0 Methyl 2.012 3255 3551 0.43 7.4 35.5 diethanolamine 6.18 HA30W 2.0 Isopropanol 2.513 3418 4102 0.31 6.1 30.5 amine 6.19 HA30W 2.0 Diisopropanol 2.0 133282 4102 0.38 7.0 34.7 amine 6.20 HA30W 2.0 Triisopropanol 2.0 12 30913198 0.36 6.9 32.3 amine 6.21 HA30W ″ Triisopropanol ″ 10 2774 2484 0.468.1 38.2 amine 6.22 HA30W 2.0 Dimethyl 2.0 16 3080 3187 0.56 9.8 46.0isopropanolamine Ti(OiPr)₄ was dissolved in 2 eq of oxalic acidsolution, then base was added to partially neutralize the acid. Thesolution was then added to virgin HA30W and dried. Each catalystcontained 3.5 wt % Ti and was activated at 650° C. Runs were conductedat 105° C., 550 psig. * Dried at 100° C. and then washed with waterbefore drying again. † Dried at up to 650° C. in N₂. ‡ Dried at up to650° C. in air. OA: oxalic acid, DMAE: Dimethylaminoethanol

Example 7: pH Adjustment with Other Amines

The next series of experiments studied the ability of a variety of otheramines to partially neutralize an acidic Ti-containing solution andcreate an STM capable of providing effective titanation to a catalyst.The experimental approach was essentially identical to the methoddescribed in Example 5 and the results are shown in Table 7. A generaltrend of higher performance from bulkier amines was observed but wassometimes compromised by a lack of solubility, e.g., 2-ethylhexylamineor DABCO. Bases capable of delocalizing a positive charge obtained uponprotonation displayed very good performance; examples include DBU,creatine, and imidazole.

TABLE 7 Oxalic Acid with Other Amines Ind. Time Prod. Activity MI |10HLMI Run No. Base Base/Ti min g/g g/g-h dg/min dg/min dg/min 7.1Hydrazine 2.00 12 3304 2643 0.00 2.3 12.4 7.2 Hydroxylamine 2.50 4 16381694 0.23 5.4 27.1 7.3 Trimethylamine 2.00 15 3143 4013 0.38 7.2 35.57.4 Hexylamine 2.00 9 3312 3896 0.54 8.2 45.1 7.5 t-Butylamine + 1.0 +1.0 10 3257 3832 0.45 5.0 38.0 Ethanolamine 7.6 2-Ethylhexylamine 2.00Precipitated 7.7 2-Ethylhexylamine* 2.00 Precipitated 7.8Ethylenediamine 0.40 Precipitated 7.9 Diethylene triamine 2.00Precipitated 7.10 Diethylene triamine 0.50 Precipitated 7.11 Formamide2.00 13 2642 2366 0.15 3.7 18.8 7.12 Methylformamide 2.00 11 3294 40340.31 6.0 30.0 7.13 Dimethylformamide 2.00 11 3839 2992 0.59 11.4 43.67.14 Acetamide 2.00 14 3129 4941 0.39 6.7 32.8 7.15 DBU 2.00 7 3390 36320.56 10.0 48.1 7.16 DABCO 2.00 Precipitated 7.17 DABCO 2.00 Precipitated7.18 N-Methylaniline 2.40 12 3044 3728 0.66 11.6 55.8 7.19 ″ ″ 17 1711567 0.38 7.8 41.2 7.20 Imidazole 2.00 6 2785 2457 0.32 6.6 32.2 7.21Pyrazole 2.00 9 3062 3467 0.21 4.6 22.5 7.22 Glycine 2.00 15 3150 30980.09 2.7 13.6 7.23 Dimethylglycine 2.00 10 3297 3243 0.18 4.2 21.5 7.24Arginine 1.85 17 3244 3089 0.08 2.6 14.4 7.25 ″ ″ 13 3142 2945 2.3 7.26Creatine 2.00 6 2733 4316 0.47 8.5 42.2 7.27 ″ ″ 5 3422 3366 0.34 6.935.0 7.28 Melamine 2.00 Precipitated 7.29 Uricil 2.00 Precipitated 7.30Cyanuric acid 2.00 Precipitated 7.31 Methyl carbamate 2.00 14 2930 29800.14 3.5 18.2 7.32 Dimethyl carbamate 2.00 14 3380 3219 0.26 5.3 25.7Ti(OiPr)₄ was dissolved in 2 eq of oxalic acid solution, then base wasadded to partially neutralize the acid. This solution was then added tovirgin HA30W and dried. Each catalyst contained 3.5 wt % Ti and wasactivated at 650° C. Runs were conducted at 105° C., 550 psig.*Ethylhexylamine was added directly to the oxalic acid solution.

Example 8: pH Adjustment with Inorganic Bases

The next series of experiments studied the ability of inorganic bases topartially neutralize an acidic Ti-containing solution and create an STMcapable of providing effective titanation to a catalyst. Theexperimental approach was essentially identical to the method describedin Example 5 and the results are shown in Table 8. This approach wasgenerally unsuccessful. Not wishing to be limited by theory, higherpermittivity may have been an influence, but the presence of divalent ortrivalent metal cations could have interfered with the delicate balanceof surface charge between silica and titania. Runs 8.2 and 8.3 werepartially successful and co-introduced equal amounts of Al ions with Tiions. Three equivalents of oxalic acid were added to dissolve twoequivalents of metal (1 Ti(OiPr)₄+1 Al(OH)₃) which is a lower acid/metalratio than in most of the other experiments described herein. Run 8.3included partial neutralization of the acid with tetraethylammoniumhydroxide in an amount of 1.5 equivalents of base per Ti. This is alower base/metal ratio than in most of the other experiments describedherein but an increase in HLMI was observed. Not wishing to be limitedby theory, coating titania onto alumina may be more facile than coatingtitania onto silica. Ti and Al are both metals and the chemicalproperties of the two are in many ways more similar than the chemicalproperties of Ti and Si.

TABLE 8 Oxalic Acid with Inorganic Bases Ind. Time Prod. Activity MI |10HLMI Run No. Description min g/g g/g-h dg/min dg/min dg/min 8.1 Ti + 2OA + 1.2 Al(OH)₃ 10 3333 2273 0.0 0.65 4.7 8.2 Ti + 3 OA + Al(OH)₃ 173286 2987 0.0 1.43 8.0 8.3 Ti + 3 OA + Al(OH)₃ + 12 3205 4274 0.0 2.0411.2 1.5 NEt₄OH 8.4 Ti + 2 OA + 1.4 Mg(OH)₂ 12 3199 3047 0.0 0.80 5.18.5 Ti + 2 OA + 1 Mg(OH)₂ 12 3220 3645 0.0 1.04 6.1 8.6 Ti + 2 OA + 0.4ZnO Not soluble Ti(OiPr)₄ was dissolved in OA solution to which othermetals were added. This solution was then added to virgin HA30W anddried. Each catalyst contained 3.5 wt % Ti and was activated at 650° C.Runs were conducted at 105° C., 550 psig. OA = oxalic acid

Example 9: Solvation of Ti by Other Acids

The next series of experiments studied the ability of carboxylic acidsother than oxalic acid to be partially neutralized and create an STMcapable of providing effective titanation to a catalyst. Theexperimental approach was essentially identical to the method describedin Example 4 and the results are shown in Table 9. The experiments weregenerally less successful than experiments using oxalic acid. Several ofthe experiments added two equivalents of base per Ti, which was morethan needed to obtain a pH value of 4.0 because the acids tested wereweaker than oxalic acid. In other experiments, base was added until agreen-hued endpoint of the bromocresol green indicator was reached,indicating a pH value of 4.0. An example of this method is Run 9.7 wherethe use of citric acid and tetramethylammonium hydroxide produced highlyeffective titanation as evidenced by an HLMI value of almost 30. Run9.14 indicated that titanyl sulfate, in the absence of a carboxylicacid, could be partially neutralized by DMAE to produce moderatelyeffective titanation.

TABLE 9 Solvation of Ti by Other Acids and Partial Neutralization Ind.Time Prod. Activity MI |10 HLMI Run No. Description min g/g g/g-h dg/mindg/min dg/min 9.1 Ti + 2 Maleic Acid + 2 NEt₄OH Not dissolved 9.2 Ti + 2Lactic acid + 2 NEt₄OH  9 3348 3720 0.05 2.2 12.1 9.3 Ti + 2 LacticAcid + 0.3 Ethanolamine, 12 3803 3406 0.02 1.8 10.1 green endpoint 9.4Ti + 1.5 NMe₄OH + 1.5 DMAE Gelled then 1 Malonic acid 9.5 Ti + 4 Malicacid + 1.6 Ethanolamine, 13 3112 2964 0.10 3.1 16.1 green endpoint 9.6Ti + 2 Citric acid + 2 NEt₄OH 14 3218 3510 0.10 3.0 15.4 9.7 Ti + 2.5Citric acid + 1.66 NMe₄OH 17 3280 4278 0.29 6.0 29.5 9.8 Ti + 5 Glycolicacid + 1.6 Ethanolamine, 11 2930 2790 0.16 3.9 19.9 green endpoint 9.9Ti + 5 Glycolic acid + 1.6 Ethanolamine,  8 3270 2582 0.10 3.3 17.4green endpoint 9.10 0.5 NMe₄OH + 1.5 DMAE, then Ti  9 4568 3754 0.21 4.924.1 then 4.6 Glycolic acid 9.11 Ti + 3 Glyoxylic Acid + 3 NEt₄OH 223284 2855 0.00 1.1 6.5 9.12 Ti + HNO₃ + NH₄OH until ppt* 15 3174 36620.01 0.7 4.9 9.13 Ti + Dihydroxyfumaric acid Not dissolved 9.14 TiOSO₄ +DMAE 10 3197 2863 0.022 1.7 9.8 An attempt was made to dissolveTi(OiPr)₄ into various acidic solutions, followed by partialneutralization by base. This solution was then added to virgin HA30W anddried to yield 3.5 wt % Ti, followed by activation at 650° C. *969MSDMAE = dimethylaminoethanol

ADDITIONAL DISCLOSURE

The following enumerated aspects of the present disclosure are providedas non-limiting examples.

A first aspect, which is a method comprising a) contacting a solvent anda carboxylic acid to form an acidic mixture wherein a weight ratio ofsolvent to carboxylic acid in the acidic mixture is from about 1:1 toabout 100:1; b) contacting a titanium-containing compound and the acidicmixture to form an acidic titanium mixture wherein an equivalent molarratio of titanium-containing compound to carboxylic acid in the acidictitanium mixture is from about 1:1 to about 1:4; c) contacting anitrogen-containing compound and the acidic titanium mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in thesolubilized titanium mixture is from about 1:1 to about 1:4 and a pH ofthe solubilized titanium mixture is less than about 5.5; and d)contacting a chromium-silica support comprising from about 0.1 wt. % toabout 20 wt. % water and the solubilized titanium mixture to form anaddition product and drying the addition product by heating to atemperature in a range of from about 50° C. to about 150° C. andmaintaining the temperature in the range of from about 50° C. to about150° C. for a time period of from about 30 minutes to about 6 hours toform a pre-catalyst.

A second aspect which is the method of the first aspect furthercomprising e) calcining the pre-catalyst by heating the pre-catalyst toa temperature in a range of from about 400° C. to about 1000° C. andmaintaining the temperature of the pre-catalyst in the range of fromabout 400° C. to about 1000° C. for a time period of from about 1 minuteto about 24 hours to form a catalyst.

A third aspect which is the method of any of the first two aspectswherein the equivalent molar ratio of titanium-containing compound tocarboxylic acid in the acidic titanium mixture is about 1:2 and theequivalent molar ratio of titanium-containing compound tonitrogen-containing compound in the solubilized titanium mixture isabout 1:2.

A fourth aspect which is the method of any of the first three aspectswherein the pH of the solubilized titanium mixture is in a range of fromabout 3.5 to about 4.5.

A fifth aspect which is the method of any of the first four aspectswherein (c) comprises neutralizing the acidic titanium mixture andwherein the neutralizing is a partial neutralizing or a completeneutralizing.

A sixth aspect which is the method of any of the first five aspectswherein the nitrogen-containing compound has Structure 1, Structure 2,Structure 3, Structure 4, Structure 5, or Structure 6: where R¹, R², R³,R⁹, R¹⁰ and R¹¹ are each independently hydrogen, a C₁ to C₁₂ organylgroup, or a C₆ to C₁₂ aryl group; R⁴ is a C₁ to C₁₂ organyl group or aC₆ to C₁₂ aryl group; R⁵ and R⁶ are each independently hydrogen, a C₁ toC₆ organyl group, or a C₆ to C₁₂ aryl group; R⁷ and R⁸ are eachindependently hydrogen or CH₃; R¹² is a branched C₁ to C₆ alkyl group, acyclic C₁ to C₆ alkyl group, or a linear C₁ to C₆ alkyl group; x is aninteger from 1 to 4, y is an integer from 1 to 12, and Z is oxygen orsulfur.

A seventh aspect which is the method of any of the first six aspectswherein the nitrogen-containing compound comprises an alkanolamine, anamine, an ammonium hydroxide, a hydroxylamine, a urea, or a combinationthereof.

An eighth aspect which is the method of any of the first seven aspectswherein the nitrogen-containing compound comprises acetamide, ammonia,ammonium hydroxide, tert-butyl amine, creatine, N,N′-dibutyl urea,diethanol amine, diisopropanol amine, dimethylaminoethanol, dimethylcarbamate, dimethyl formamide, dimethyl glycine, dimethylisopropanolamine, N,N′-dimethyl urea, ethanol amine, glycol amine, hexyl amine,hydroxyl amine, imidazole, isopropanol amine, N-methyl aniline,methyldiethanol amine, methyl formamide, pyrazole, tetraethylammoniumhydroxide, tetramethylammonium hydroxide, triethanol amine,triisopropanol amine, trimethyl amine, urea, or a combination thereof.

A ninth aspect which is the method of any of the first eight aspectswherein the carboxylic acid comprises a C₁ to C₁₅ monocarboxylic acid, aC₁ to C₁₅ dicarboxylic acid, a C₁ to C₁₅ tricarboxylic acid, a C₁ to C₁₅α-hydroxycarboxylic acid, or a combination thereof.

A tenth aspect which is the method of any of the first nine aspectswherein the carboxylic acid comprises acetic acid, citric acid, glycolicacid, oxalic acid, phosphonoacetic acid, or a combination thereof.

An eleventh aspect which is the method of any of the first ten aspectswherein the titanium-containing compound comprises a titanium hydroxide,a titanic acid, a titanyl sulfate, a titanium(IV) alkoxide, a titanylacetylacetonate, a titanium(IV) halide, or a combination thereof.

A twelfth aspect which is the method of any of the first eleven aspectswherein the titanium-containing compound comprises titanium(IV)isopropoxide.

A thirteenth aspect which is the method of any of the first twelveaspects wherein (d) further comprises spray drying the solubilizedtitanium mixture onto the chromium-silica support.

A fourteenth aspect which is the method of any of the first thirteenaspects wherein the chromium-silica support is characterized by asurface area of from about 100 m²/gram to about 1000 m²/gram and a porevolume of from about 1.0 cm³/gram to about 2.5 cm³/gram.

A fifteenth aspect which is the method of any of the first fourteenaspects wherein an amount of chromium present in the catalyst rangesfrom about 0.01 wt. % to about 10 wt. % by total weight of the catalystand an amount of titanium present in the catalyst ranges from about 0.01wt. % to about 10 wt. % by total weight of the catalyst.

A sixteenth aspect which is the method of any of the first fifteenaspects wherein the solvent comprises an aqueous solvent, an alcohol, anorganic solvent, or a combination thereof.

A seventeenth aspect which is a method of forming an ethylene polymercomprising contacting the catalyst formed by the method of the secondaspect with an ethylene monomer under conditions suitable for formationof the ethylene polymer and recovering the ethylene polymer.

An eighteenth aspect which is the method of the seventeenth aspectwherein the ethylene polymer has a high load melt index (HLMI) that isfrom about 1.5 to about 15 times greater than the HLMI of an ethylenepolymer prepared with an otherwise similar catalyst produced in theabsence of a nitrogen-containing compound.

A nineteenth aspect which is a method of a) contacting a solvent and acarboxylic acid to form an acidic mixture wherein a weight ratio ofsolvent to carboxylic acid in the acidic mixture is from about 1:1 toabout 100:1; b) contacting a titanium-containing compound and the acidicmixture to form an acidic titanium mixture wherein an equivalent molarratio of titanium-containing compound to carboxylic acid in the acidictitanium mixture is from about 1:1 to about 1:4; c) contacting anitrogen-containing compound and the acidic titanium mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in thesolubilized titanium mixture is from about 1:1 to about 1:4 and a pH ofthe solubilized titanium mixture is in a range of from about 3.5 toabout 4.5; d) contacting a silica support comprising from about 0.1 wt.% to about 20 wt. % water and the solubilized titanium mixture to form atitanated support and drying the titanated support by heating to atemperature in a range of from about 50° C. to about 150° C. andmaintaining the temperature in the range of from about 50° C. to about150° C. for a time period of from about 30 minutes to about 6 hours toform a dried titanated support; and e) contacting, to form apre-catalyst, a chromium-containing compound and at least one materialselected from the group consisting of the silica support, the titanatedsupport, and the dried titanated support.

A twentieth aspect which is the method of the nineteenth aspect furthercomprising: f) calcining the pre-catalyst by heating to a temperature ina range of from about 400° C. to about 1000° C. and maintaining thetemperature in the range of from about 400° C. to about 1000° C. for atime period of from about 1 minute to about 24 hours to form a catalyst.

A twenty-first aspect which is the method of the nineteenth aspectwherein (c) comprises neutralizing the acidic titanium mixture andwherein the neutralizing is a partial neutralizing or a completeneutralizing.

A twenty-second aspect which is a method comprising: a) contacting atitanium-containing compound and a nitrogen-containing compound to forma basic mixture wherein an equivalent molar ratio of titanium-containingcompound to nitrogen-containing compound in the basic mixture is fromabout 1:1 to about 1:4; b) contacting a solvent and a carboxylic acid toform an acidic mixture wherein a weight ratio of solvent to carboxylicacid in the acidic mixture is from about 1:1 to about 100:1; c)contacting the basic mixture and the acidic mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to carboxylic acid in the solubilizedtitanium mixture is from about 1:1 to about 1:4 and a pH of thesolubilized titanium mixture is in a range of from about 3.5 to about4.5; and d) contacting a chromium-silica support comprising from about0.1 wt. % to about 20 wt. % water and the solubilized titanium mixtureto form an addition product and drying the addition product by heatingto a temperature in a range of from about 50° C. to about 150° C. andmaintaining the temperature in the range of from about 50° C. to about150° C. for a time period of from about 30 minutes to about 6 hours toform a pre-catalyst.

A twenty-third aspect which is the method of the twenty-second aspectfurther comprising: e) calcining the pre-catalyst by heating thepre-catalyst to a temperature in a range of from about 400° C. to about1000° C. and maintaining the temperature of the pre-catalyst in therange of from about 400° C. to about 1000° C. for a time period of fromabout 1 minute to about 24 hours to form a catalyst.

A twenty-fourth aspect which is a method comprising: a) contacting atitanium-containing compound and a nitrogen-containing compound to forma basic mixture wherein an equivalent molar ratio of titanium-containingcompound to nitrogen-containing compound in the basic mixture is fromabout 1:1 to about 1:4; b) contacting a solvent and a carboxylic acid toform an acidic mixture wherein a weight ratio of solvent to carboxylicacid in the acidic mixture is from about 1:1 to about 100:1; c)contacting the basic mixture and the acidic mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to carboxylic acid in the solubilizedtitanium mixture is from about 1:1 to about 1:4 and a pH of thesolubilized titanium mixture is in a range of from about 3.5 to about4.5; d) contacting a silica support comprising from about 0.1 wt. % toabout 20 wt. % water and the solubilized titanium mixture to form atitanated support and drying the titanated support by heating to atemperature in a range of from about 50° C. to about 150° C. andmaintaining the temperature in the range of from about 50° C. to about150° C. for a time period of from about 30 minutes to about 6 hours toform a dried titanated support; and e) contacting, to form apre-catalyst, a chromium-containing compound and at least one materialselected from the group consisting of the silica support, the titanatedsupport, and the dried titanated support.

A twenty-fifth aspect which is the method of the twenty-fourth aspectfurther comprising: f) calcining the pre-catalyst by heating thepre-catalyst to a temperature in a range of from about 400° C. to about1000° C. and maintaining the temperature of the pre-catalyst in therange of from about 400° C. to about 1000° C. for a time period of fromabout 1 minute to about 24 hours to form a catalyst.

A twenty-sixth aspect which is a pre-catalyst composition comprising: a)a silica support comprising silica wherein an amount of silica is in arange of from about 70 wt. % to about 95 wt. % based upon a total weightof the silica support; b) a chromium-containing compound wherein anamount of chromium is in a range of from about 0.1 wt. % to about 5 wt.% based upon the amount of silica; c) a titanium-containing compoundwherein an amount of titanium is in a range of from about 0.1 wt. % toabout 20 wt. % based upon the amount of silica; d) a carboxylic acidwherein an equivalent molar ratio of titanium-containing compound tocarboxylic acid is in a range of from about 1:1 to about 1:10; and e) anitrogen-containing compound with a molecular formula containing atleast one nitrogen atom wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound is in arange of from about 1:0.5 to about 1:10.

A twenty-seventh aspect which is the pre-catalyst composition of thetwenty-sixth aspect wherein the carboxylic acid comprises a C₁ to C₁₅monocarboxylic acid, a C₁ to C₁₅ dicarboxylic acid, a C₁ to C₁₅tricarboxylic acid, a C₁ to C₁₅ α-hydroxycarboxylic acid, or acombination thereof.

A twenty-eighth aspect which is the pre-catalyst composition of eitherof the twenty-sixth or twenty-seventh aspects wherein the carboxylicacid comprises acetic acid, citric acid, glycolic acid, oxalic acid,phosphonoacetic acid, or a combination thereof.

A twenty-ninth aspect which is the pre-catalyst composition of any ofthe twenty-sixth through twenty-eighth aspects wherein thenitrogen-containing compound comprises an alkanolamine, an amide, anamine, an alkylamine, an ammonium hydroxide, an aniline, ahydroxylamine, a urea, or a combination thereof.

A thirtieth aspect which is the pre-catalyst composition of any of thetwenty-sixth through twenty-ninth aspects wherein thenitrogen-containing compound comprises acetamide, acryl amide, allylamine, ammonia, ammonium hydroxide, butyl amine, tert-butyl amine,N,N′-dibutyl urea, creatine, creatinine, diethanol amine, diethylhydroxyamine, diisopropanol amine, dimethylaminoethanol, dimethyl carbamate,dimethyl formamide, dimethyl glycine, dimethylisopropanol amine,N,N′-dimethyl urea, ethanol amine, ethyl amine, glycol amine, hexylamine, hydroxyamine, imidazole, isopropanol amine, methacryl amide,methyl amine, N-methyl aniline, N-methyl-2-propanol amine,methyldiethanol amine, methyl formamide, propyl amine, 2-propanol amine,pyrazole, pyrrolidine, pyrrolidinone, succinimide, tetraethylammoniumhydroxide, tetramethylammonium hydroxide, triethanol amine,triisopropanol amine, trimethyl amine, urea,1,8-diazabicyclo[5.4.0]undec-7-ene, or a combination thereof.

A thirty-first aspect which is the pre-catalyst composition of any ofthe twenty-sixth through thirtieth aspects wherein the silica supportfurther comprises alumina.

A thirty-second aspect which is the pre-catalyst composition of any ofthe twenty-sixth through thirty-first aspects wherein the silica supportis characterized by a surface area of from about 100 m²/gram to about1000 m²/gram and a pore volume of from about 1.0 cm³/gram to about 2.5cm³/gram.

A thirty-third aspect which is the pre-catalyst composition of any ofthe twenty-sixth through thirty-second aspects wherein the silicasupport comprises a hydrated silica support.

A thirty-fourth aspect which is the pre-catalyst composition of any ofthe twenty-sixth through thirty-third aspects wherein the silica supportcomprises from about 1 wt. % to about 20 wt. % water based upon a totalweight of the silica support.

A thirty-fifth aspect which is a pre-catalyst composition comprising: a)a silica support comprising silica wherein an amount of silica is in arange of from about 70 wt. % to about 95 wt. % based upon a total weightof the silica support; b) a chromium-containing compound wherein anamount of chromium is in a range of from about 0.1 wt. % to about 5 wt.% based upon the amount of silica; and c) a titano-organic salt, whereinthe titano-organic salt comprises titanium, a protonatednitrogen-containing compound and a carboxylate, and wherein: i) anamount of titanium is in a range of from about 0.1 wt. % to about 20 wt.% based upon the amount of silica; ii) an equivalent molar ratio oftitanium to carboxylate is in a range of from about 1:1 to about 1:10;and iii) an equivalent molar ratio of titanium to protonatednitrogen-containing compound is in a range of from about 1:0.5 to about1:10.

A thirty-sixth aspect which is the pre-catalyst composition of thethirty-fifth aspect wherein the protonated nitrogen-containing compoundcomprises a protonated alkanolamine, a protonated amide, a protonatedamine, a protonated alkylamine, a protonated ammonium hydroxide, aprotonated aniline, a protonated hydroxylamine, a protonated urea, or acombination thereof.

A thirty-seventh aspect which is the pre-catalyst composition of thethirty-fifth aspect wherein the protonated nitrogen-containing compoundcomprises protonated acetamide, protonated acryl amide, protonated allylamine, ammonium, protonated ammonium hydroxide, protonated butyl amine,protonated tert-butyl amine, protonated N,N′-dibutyl urea, protonatedcreatine, protonated creatinine, protonated diethanol amine, protonateddiethylhydroxy amine, protonated diisopropanol amine, protonateddimethylaminoethanol, protonated dimethyl carbamate, protonated dimethylformamide, protonated dimethyl glycine, protonated dimethylisopropanolamine, protonated N,N′-dimethyl urea, protonated ethanol amine,protonated ethyl amine, protonated glycol amine, protonated hexyl amine,protonated hydroxyamine, protonated imidazole, protonated isopropanolamine, protonated methacryl amide, protonated methyl amine, protonatedN-methyl aniline, protonated N-methyl-2-propanol amine, protonatedmethyldiethanol amine, protonated methyl formamide, protonated propylamine, protonated 2-propanol amine, protonated pyrazole, protonatedpyrrolidine, protonated pyrrolidinone, protonated succinimide,protonated tetraethylammonium hydroxide, protonated tetramethylammoniumhydroxide, protonated triethanol amine, protonated triisopropanol amine,protonated trimethyl amine, protonated urea, protonated1,8-diazabicyclo[5.4.0]undec-7-ene, or a combination thereof.

A thirty-eighth aspect which is the pre-catalyst composition of any ofthe thirty-fifth through thirty-seventh aspects wherein the carboxylatecomprises a C₁ to C₁₅ monocarboxylate, a C₁ to C₁₅ dicarboxylate, a C₁to C₁₅ tricarboxylate, a C₁ to C₁₅ α-hydroxycarboxylate, or acombination thereof.

A thirty-ninth aspect which is the pre-catalyst composition of any ofthe thirty-fifth through thirty-eighth aspects wherein the carboxylatecomprises acetate, citrate, glycolate, oxalate, phosphonoacetate, or acombination thereof.

A fortieth aspect which is the pre-catalyst composition of any of thethirty-fifth through thirty-ninth aspects wherein the silica supportfurther comprises alumina.

A forty-first aspect which is the pre-catalyst composition of any of thethirty-fifth through fortieth aspects wherein the silica support ischaracterized by a surface area of from about 100 m²/gram to about 1000m²/gram and a pore volume of from about 1.0 cm³/gram to about 2.5cm³/gram.

A forty-second aspect which is the pre-catalyst composition of any ofthe thirty-fifth through forty-first aspects wherein the silica supportcomprises a hydrated silica support.

A forty-third aspect which is the pre-catalyst composition of any of thethirty-fifth through forty-second aspects wherein the silica supportcomprises from about 1 wt. % to about 20 wt. % water based upon a totalweight of the silica support.

A forty-fourth aspect which is a pre-catalyst composition comprising: a)a silica support comprising silica wherein an amount of silica is in arange of from about 70 wt. % to about 95 wt. % based upon a total weightof the silica support; b) a chromium-containing compound wherein anamount of chromium is in a range of from about 0.1 wt. % to about 5 wt.% based upon the amount of silica; c) a titanium-containing compoundwherein an amount of titanium is in a range of from about 0.01 wt. % toabout 0.1 wt. % based upon the amount of silica; d) a carboxylic acidwherein an equivalent molar ratio of titanium-containing compound tocarboxylic acid is in a range of from about 1:1 to about 1:10; and e) anitrogen-containing compound with a molecular formula containing atleast one nitrogen atom wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound is in arange of from about 1:0.5 to about 1:10.

A forty-fifth aspect which is a pre-catalyst composition prepared by amethod comprising: a) contacting a solvent and a carboxylic acid to forman acidic mixture wherein a weight ratio of solvent to carboxylic acidin the acidic mixture is from about 1:1 to about 100:1; b) contacting atitanium-containing compound and the acidic mixture to form an acidictitanium mixture wherein an equivalent molar ratio oftitanium-containing compound to carboxylic acid in the acidic titaniummixture is from about 1:1 to about 1:4; c) contacting anitrogen-containing compound and the acidic titanium mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in thesolubilized titanium mixture is from about 1:1 to about 1:4 and a pH ofthe solubilized titanium mixture is less than about 5.5; and d)contacting a chromium-silica support comprising from about 0.1 wt. % toabout 20 wt. % water and the solubilized titanium mixture to form anaddition product and drying the addition product by heating to atemperature in a range of from about 50° C. to about 150° C. andmaintaining the temperature in the range of from about 50° C. to about150° C. for a time period of from about 30 minutes to about 6 hours toform the pre-catalyst.

The terms “a”, “an”, and “the” are intended, unless specificallyindicated otherwise, to include plural alternatives, e.g., at least one.Herein, while methods and processes are described in terms of“comprising” various components or steps, the methods and processes canalso “consist essentially of” or “consist of” the various components orsteps. A particular feature of the disclosed subject matter can bedisclosed as follows: Feature X can be A, B, or C. It is alsocontemplated that for each feature the statement can also be phrased asa listing of alternatives such that the statement “Feature X is A,alternatively B, or alternatively C” is also an aspect of the presentdisclosure whether or not the statement is explicitly recited.

While various aspects of the present disclosure have been shown anddescribed, modifications thereof can be made by one skilled in the artwithout departing from the spirit and teachings of the presentdisclosure. The aspects of the present disclosure described herein areexemplary only, and are not intended to be limiting. Many variations andmodifications of the present disclosure are possible and are within thescope of the present disclosure. Where numerical ranges or limitationsare expressly stated, such express ranges or limitations should beunderstood to include iterative ranges or limitations of like magnitudefalling within the expressly stated ranges or limitations (e.g., “fromabout 1 to about 10” includes, 2, 3, 4, etc.; “greater than 0.10”includes 0.11, 0.12, 0.13, etc.). Use of the term “optionally” withrespect to any element of a claim is intended to mean that the subjectelement is required, or alternatively, is not required. Bothalternatives are intended to be within the scope of the claim. Use ofbroader terms such as “comprises”, “includes”, “having, etc. should beunderstood to provide support for narrower terms such as “consistingof”, “consisting essentially of”, “comprised substantially of”, etc.

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an aspect of thepresent disclosure. Thus, the claims are a further description and arean addition to the aspects of the present disclosure. The discussion ofa reference in the present disclosure is not an admission that it isprior art to the present disclosure, especially any reference that mayhave a publication date after the priority date of this application. Thepresent disclosure of all patents, patent applications, and publicationscited herein are hereby incorporated by reference, to the extent thatthey provide exemplary, procedural or other details supplementary tothose set forth herein.

All publications, patent applications, and patents mentioned herein areincorporated by reference in their entirety. In the event of conflict,the present specification, including definitions, is intended tocontrol. With respect to all ranges disclosed herein, such ranges areintended to include any combination of the mentioned upper and lowerlimits even if the particular combination is not specifically listed.

What is claimed is:
 1. A method comprising: a) contacting a solvent anda carboxylic acid to form an acidic mixture wherein a weight ratio ofsolvent to carboxylic acid in the acidic mixture is from about 1:1 toabout 100:1; b) contacting a titanium-containing compound and the acidicmixture to form an acidic titanium mixture wherein an equivalent molarratio of titanium-containing compound to carboxylic acid in the acidictitanium mixture is from about 1:1 to about 1:4; c) contacting anitrogen-containing compound and the acidic titanium mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in thesolubilized titanium mixture is from about 1:1 to about 1:4 and a pH ofthe solubilized titanium mixture is less than about 5.5; and d)contacting a chromium-silica support comprising from about 0.1 wt. % toabout 20 wt. % water and the solubilized titanium mixture to form anaddition product and drying the addition product by heating to atemperature in a range of from about 50° C. to about 150° C. andmaintaining the temperature in the range of from about 50° C. to about150° C. for a time period of from about 30 minutes to about 6 hours toform a pre-catalyst.
 2. The method of claim 1 further comprising: e)calcining the pre-catalyst by heating the pre-catalyst to a temperaturein a range of from about 400° C. to about 1000° C. and maintaining thetemperature of the pre-catalyst in the range of from about 400° C. toabout 1000° C. for a time period of from about 1 minute to about 24hours to form a catalyst.
 3. The method of claim 1 wherein theequivalent molar ratio of titanium-containing compound to carboxylicacid in the acidic titanium mixture is about 1:2 and the equivalentmolar ratio of titanium-containing compound to nitrogen-containingcompound in the solubilized titanium mixture is about 1:2.
 4. The methodof claim 1 wherein the pH of the solubilized titanium mixture is in arange of from about 3.5 to about 4.5.
 5. The method of claim 1 wherein(c) comprises neutralizing the acidic titanium mixture and wherein theneutralizing is a partial neutralizing or a complete neutralizing. 6.The method of claim 1 wherein the nitrogen-containing compound hasStructure 1, Structure 2, Structure 3, Structure 4, Structure 5, orStructure 6:

where R¹, R², R³, R⁹, R¹⁰ and R¹¹ are each independently hydrogen, a C₁to C₁₂ organyl group, or a C₆ to C₁₂ aryl group; R⁴ is a C₁ to C₁₂organyl group or a C₆ to C₁₂ aryl group; R⁵ and R⁶ are eachindependently hydrogen, a C₁ to C₆ organyl group, or a C₆ to C₁₂ arylgroup; R⁷ and R⁸ are each independently hydrogen or CH₃; R¹² is abranched C₁ to C₆ alkyl group, a cyclic C₁ to C₆ alkyl group, or alinear C₁ to C₆ alkyl group; x is an integer from 1 to 4, y is aninteger from 1 to 12, and Z is oxygen or sulfur.
 7. The method of claim1 wherein the nitrogen-containing compound comprises an alkanolamine, anamine, an ammonium hydroxide, a hydroxylamine, a urea, or a combinationthereof.
 8. The method of claim 1 wherein the nitrogen-containingcompound comprises acetamide, ammonia, ammonium hydroxide, tert-butylamine, creatine, N,N′-dibutyl urea, diethanol amine, diisopropanolamine, dimethylaminoethanol, dimethyl carbamate, dimethyl formamide,dimethyl glycine, dimethylisopropanol amine, N,N′-dimethyl urea, ethanolamine, glycol amine, hexyl amine, hydroxyl amine, imidazole, isopropanolamine, N-methyl aniline, methyldiethanol amine, methyl formamide,pyrazole, tetraethylammonium hydroxide, tetramethylammonium hydroxide,triethanol amine, triisopropanol amine, trimethyl amine, urea, or acombination thereof.
 9. The method of claim 1 wherein the carboxylicacid comprises a C₁ to C₁₅ monocarboxylic acid, a C₁ to C₁₅ dicarboxylicacid, a C₁ to C₁₅ tricarboxylic acid, a C₁ to C₁₅ α-hydroxycarboxylicacid, or a combination thereof.
 10. The method of claim 1 wherein thecarboxylic acid comprises acetic acid, citric acid, glycolic acid,oxalic acid, phosphonoacetic acid, or a combination thereof.
 11. Themethod of claim 1 wherein the titanium-containing compound comprises atitanium hydroxide, a titanic acid, a titanyl sulfate, a titanium(IV)alkoxide, a titanyl acetylacetonate, a titanium(IV) halide, or acombination thereof.
 12. The method of claim 1 wherein thetitanium-containing compound comprises titanium(IV) isopropoxide. 13.The method of claim 1 wherein (d) further comprises spray drying thesolubilized titanium mixture onto the chromium-silica support.
 14. Amethod comprising: a) contacting a solvent and a carboxylic acid to forman acidic mixture wherein a weight ratio of solvent to carboxylic acidin the acidic mixture is from about 1:1 to about 100:1; b) contacting atitanium-containing compound and the acidic mixture to form an acidictitanium mixture wherein an equivalent molar ratio oftitanium-containing compound to carboxylic acid in the acidic titaniummixture is from about 1:1 to about 1:4; c) contacting anitrogen-containing compound and the acidic titanium mixture to form asolubilized titanium mixture wherein an equivalent molar ratio oftitanium-containing compound to nitrogen-containing compound in thesolubilized titanium mixture is from about 1:1 to about 1:4 and a pH ofthe solubilized titanium mixture is in a range of from about 3.5 toabout 4.5; d) contacting a silica support comprising from about 0.1 wt.% to about 20 wt. % water and the solubilized titanium mixture to form atitanated support and drying the titanated support by heating to atemperature in a range of from about 50° C. to about 150° C. andmaintaining the temperature in the range of from about 50° C. to about150° C. for a time period of from about 30 minutes to about 6 hours toform a dried titanated support; and e) contacting, to form apre-catalyst, a chromium-containing compound and at least one materialselected from the group consisting of the silica support, the titanatedsupport, and the dried titanated support.
 15. The method of claim 14further comprising: f) calcining the pre-catalyst by heating to atemperature in a range of from about 400° C. to about 1000° C. andmaintaining the temperature in the range of from about 400° C. to about1000° C. for a time period of from about 1 minute to about 24 hours toform a catalyst.
 16. The method of claim 14 wherein (c) comprisesneutralizing the acidic titanium mixture and wherein the neutralizing isa partial neutralizing or a complete neutralizing.
 17. A methodcomprising: a) contacting a titanium-containing compound and anitrogen-containing compound to form a basic mixture wherein anequivalent molar ratio of titanium-containing compound tonitrogen-containing compound in the basic mixture is from about 1:1 toabout 1:4; b) contacting a solvent and a carboxylic acid to form anacidic mixture wherein a weight ratio of solvent to carboxylic acid inthe acidic mixture is from about 1:1 to about 100:1; c) contacting thebasic mixture and the acidic mixture to form a solubilized titaniummixture wherein an equivalent molar ratio of titanium-containingcompound to carboxylic acid in the solubilized titanium mixture is fromabout 1:1 to about 1:4 and a pH of the solubilized titanium mixture isin a range of from about 3.5 to about 4.5; and d) contacting achromium-silica support comprising from about 0.1 wt. % to about 20 wt.% water and the solubilized titanium mixture to form an addition productand drying the addition product by heating to a temperature in a rangeof from about 50° C. to about 150° C. and maintaining the temperature inthe range of from about 50° C. to about 150° C. for a time period offrom about 30 minutes to about 6 hours to form a pre-catalyst.
 18. Themethod of claim 17 further comprising: e) calcining the pre-catalyst byheating the pre-catalyst to a temperature in a range of from about 400°C. to about 1000° C. and maintaining the temperature of the pre-catalystin the range of from about 400° C. to about 1000° C. for a time periodof from about 1 minute to about 24 hours to form a catalyst.
 19. Amethod comprising: a) contacting a titanium-containing compound and anitrogen-containing compound to form a basic mixture wherein anequivalent molar ratio of titanium-containing compound tonitrogen-containing compound in the basic mixture is from about 1:1 toabout 1:4; b) contacting a solvent and a carboxylic acid to form anacidic mixture wherein a weight ratio of solvent to carboxylic acid inthe acidic mixture is from about 1:1 to about 100:1; c) contacting thebasic mixture and the acidic mixture to form a solubilized titaniummixture wherein an equivalent molar ratio of titanium-containingcompound to carboxylic acid in the solubilized titanium mixture is fromabout 1:1 to about 1:4 and a pH of the solubilized titanium mixture isin a range of from about 3.5 to about 4.5; d) contacting a silicasupport comprising from about 0.1 wt. % to about 20 wt. % water and thesolubilized titanium mixture to form a titanated support and drying thetitanated support by heating to a temperature in a range of from about50° C. to about 150° C. and maintaining the temperature in the range offrom about 50° C. to about 150° C. for a time period of from about 30minutes to about 6 hours to form a dried titanated support; and e)contacting, to form a pre-catalyst, a chromium-containing compound andat least one material selected from the group consisting of the silicasupport, the titanated support, and the dried titanated support.
 20. Themethod of claim 19 further comprising: f) calcining the pre-catalyst byheating the pre-catalyst to a temperature in a range of from about 400°C. to about 1000° C. and maintaining the temperature of the pre-catalystin the range of from about 400° C. to about 1000° C. for a time periodof from about 1 minute to about 24 hours to form a catalyst.